diff --git a/masque/abstract.py b/masque/abstract.py
index d43a3df..3301c66 100644
--- a/masque/abstract.py
+++ b/masque/abstract.py
@@ -1,4 +1,4 @@
-from typing import TypeVar
+from typing import Self
 import copy
 import logging
 
@@ -17,9 +17,6 @@ from .utils import rotation_matrix_2d, normalize_mirror
 logger = logging.getLogger(__name__)
 
 
-AA  = TypeVar('AA',  bound='Abstract')
-
-
 class Abstract(PortList):
     __slots__ = ('name', '_ports')
 
@@ -71,7 +68,7 @@ class Abstract(PortList):
         s += ']>'
         return s
 
-    def translate_ports(self: AA, offset: ArrayLike) -> AA:
+    def translate_ports(self, offset: ArrayLike) -> Self:
         """
         Translates all ports by the given offset.
 
@@ -85,7 +82,7 @@ class Abstract(PortList):
             port.translate(offset)
         return self
 
-    def scale_by(self: AA, c: float) -> AA:
+    def scale_by(self, c: float) -> Self:
         """
         Scale this Abstract by the given value
          (all port offsets are scaled)
@@ -100,7 +97,7 @@ class Abstract(PortList):
             port.offset *= c
         return self
 
-    def rotate_around(self: AA, pivot: ArrayLike, rotation: float) -> AA:
+    def rotate_around(self, pivot: ArrayLike, rotation: float) -> Self:
         """
         Rotate the Abstract around the a location.
 
@@ -118,7 +115,7 @@ class Abstract(PortList):
         self.translate_ports(+pivot)
         return self
 
-    def rotate_port_offsets(self: AA, rotation: float) -> AA:
+    def rotate_port_offsets(self, rotation: float) -> Self:
         """
         Rotate the offsets of all ports around (0, 0)
 
@@ -132,7 +129,7 @@ class Abstract(PortList):
             port.offset = rotation_matrix_2d(rotation) @ port.offset
         return self
 
-    def rotate_ports(self: AA, rotation: float) -> AA:
+    def rotate_ports(self, rotation: float) -> Self:
         """
         Rotate each port around its offset (i.e. in place)
 
@@ -146,7 +143,7 @@ class Abstract(PortList):
             port.rotate(rotation)
         return self
 
-    def mirror_port_offsets(self: AA, across_axis: int) -> AA:
+    def mirror_port_offsets(self, across_axis: int) -> Self:
         """
         Mirror the offsets of all shapes, labels, and refs across an axis
 
@@ -161,7 +158,7 @@ class Abstract(PortList):
             port.offset[across_axis - 1] *= -1
         return self
 
-    def mirror_ports(self: AA, across_axis: int) -> AA:
+    def mirror_ports(self, across_axis: int) -> Self:
         """
         Mirror each port's rotation across an axis, relative to its
           offset
@@ -177,7 +174,7 @@ class Abstract(PortList):
             port.mirror(across_axis)
         return self
 
-    def mirror(self: AA, across_axis: int) -> AA:
+    def mirror(self, across_axis: int) -> Self:
         """
         Mirror the Pattern across an axis
 
@@ -192,7 +189,7 @@ class Abstract(PortList):
         self.mirror_port_offsets(across_axis)
         return self
 
-    def apply_ref_transform(self: AA, ref: Ref) -> AA:
+    def apply_ref_transform(self, ref: Ref) -> Self:
         """
         Apply the transform from a `Ref` to the ports of this `Abstract`.
         This changes the port locations to where they would be in the Ref's parent pattern.
@@ -211,7 +208,7 @@ class Abstract(PortList):
         self.translate_ports(ref.offset)
         return self
 
-    def undo_ref_transform(self: AA, ref: Ref) -> AA:
+    def undo_ref_transform(self, ref: Ref) -> Self:
         """
         Apply the inverse transform from a `Ref` to the ports of this `Abstract`.
         This changes the port locations to where they would be in the Ref's target (from the parent).
diff --git a/masque/builder/builder.py b/masque/builder/builder.py
index 9d7b978..3d05e76 100644
--- a/masque/builder/builder.py
+++ b/masque/builder/builder.py
@@ -1,4 +1,4 @@
-from typing import TypeVar, Sequence, MutableMapping, Mapping
+from typing import Self, Sequence, MutableMapping, Mapping
 import copy
 import logging
 
@@ -20,10 +20,6 @@ from .utils import ell
 logger = logging.getLogger(__name__)
 
 
-BB  = TypeVar('BB',  bound='Builder')
-PP  = TypeVar('PP',  bound='Pather')
-
-
 class Builder(PortList):
     """
     TODO DOCUMENT Builder
@@ -239,7 +235,7 @@ class Builder(PortList):
         return new
 
     def plug(
-            self: BB,
+            self,
             other: Abstract | str | NamedPattern,
             map_in: dict[str, str],
             map_out: dict[str, str | None] | None = None,
@@ -247,7 +243,7 @@ class Builder(PortList):
             mirrored: tuple[bool, bool] = (False, False),
             inherit_name: bool = True,
             set_rotation: bool | None = None,
-            ) -> BB:
+            ) -> Self:
         """
         Instantiate a device `library[name]` into the current device, connecting
           the ports specified by `map_in` and renaming the unconnected
@@ -340,7 +336,7 @@ class Builder(PortList):
         return self
 
     def place(
-            self: BB,
+            self,
             other: Abstract | str | NamedPattern,
             *,
             offset: ArrayLike = (0, 0),
@@ -349,7 +345,7 @@ class Builder(PortList):
             mirrored: tuple[bool, bool] = (False, False),
             port_map: dict[str, str | None] | None = None,
             skip_port_check: bool = False,
-            ) -> BB:
+            ) -> Self:
         """
         Instantiate the device `other` into the current device, adding its
           ports to those of the current device (but not connecting any ports).
@@ -422,7 +418,7 @@ class Builder(PortList):
         self.pattern.refs.append(sp)
         return self
 
-    def translate(self: BB, offset: ArrayLike) -> BB:
+    def translate(self, offset: ArrayLike) -> Self:
         """
         Translate the pattern and all ports.
 
@@ -437,7 +433,7 @@ class Builder(PortList):
             port.translate(offset)
         return self
 
-    def rotate_around(self: BB, pivot: ArrayLike, angle: float) -> BB:
+    def rotate_around(self, pivot: ArrayLike, angle: float) -> Self:
         """
         Rotate the pattern and all ports.
 
@@ -453,7 +449,7 @@ class Builder(PortList):
             port.rotate_around(pivot, angle)
         return self
 
-    def mirror(self: BB, axis: int) -> BB:
+    def mirror(self, axis: int) -> Self:
         """
         Mirror the pattern and all ports across the specified axis.
 
@@ -468,7 +464,7 @@ class Builder(PortList):
             p.mirror(axis)
         return self
 
-    def set_dead(self: BB) -> BB:
+    def set_dead(self) -> Self:
         """
         Disallows further changes through `plug()` or `place()`.
         This is meant for debugging:
@@ -673,10 +669,10 @@ class Pather(Builder):
         return s
 
     def retool(
-            self: PP,
+            self,
             tool: Tool,
             keys: str | Sequence[str | None] | None = None,
-            ) -> PP:
+            ) -> Self:
         if keys is None or isinstance(keys, str):
             self.tools[keys] = tool
         else:
@@ -685,7 +681,7 @@ class Pather(Builder):
         return self
 
     def path(
-            self: PP,
+            self,
             portspec: str,
             ccw: SupportsBool | None,
             length: float,
@@ -693,7 +689,7 @@ class Pather(Builder):
             tool_port_names: Sequence[str] = ('A', 'B'),
             base_name: str = '_path',
             **kwargs,
-            ) -> PP:
+            ) -> Self:
         if self._dead:
             logger.error('Skipping path() since device is dead')
             return self
@@ -706,7 +702,7 @@ class Pather(Builder):
         return self.plug(Abstract(name, pat.ports), {portspec: tool_port_names[0]})
 
     def path_to(
-            self: PP,
+            self,
             portspec: str,
             ccw: SupportsBool | None,
             position: float,
@@ -714,7 +710,7 @@ class Pather(Builder):
             tool_port_names: Sequence[str] = ('A', 'B'),
             base_name: str = '_pathto',
             **kwargs,
-            ) -> PP:
+            ) -> Self:
         if self._dead:
             logger.error('Skipping path_to() since device is dead')
             return self
@@ -740,7 +736,7 @@ class Pather(Builder):
         return self.path(portspec, ccw, length, tool_port_names=tool_port_names, base_name=base_name, **kwargs)
 
     def mpath(
-            self: PP,
+            self,
             portspec: str | Sequence[str],
             ccw: SupportsBool | None,
             *,
@@ -750,7 +746,7 @@ class Pather(Builder):
             force_container: bool = False,
             base_name: str = '_mpath',
             **kwargs,
-            ) -> PP:
+            ) -> Self:
         if self._dead:
             logger.error('Skipping mpath() since device is dead')
             return self
@@ -790,7 +786,7 @@ class Pather(Builder):
 
     # TODO def path_join() and def bus_join()?
 
-    def flatten(self: PP) -> PP:
+    def flatten(self) -> Self:
         """
         Flatten the contained pattern, using the contained library to resolve references.
 
diff --git a/masque/builder/flatbuilder.py b/masque/builder/flatbuilder.py
index 6263689..6b9d93f 100644
--- a/masque/builder/flatbuilder.py
+++ b/masque/builder/flatbuilder.py
@@ -1,4 +1,4 @@
-from typing import TypeVar, Sequence, MutableMapping, Mapping
+from typing import Self, Sequence, MutableMapping, Mapping
 import copy
 import logging
 
@@ -17,9 +17,6 @@ from .utils import ell
 logger = logging.getLogger(__name__)
 
 
-BB  = TypeVar('BB',  bound='FlatBuilder')
-
-
 class FlatBuilder(PortList):
     """
     TODO DOCUMENT FlatBuilder
@@ -173,7 +170,7 @@ class FlatBuilder(PortList):
         return new
 
     def plug(
-            self: BB,
+            self,
             other: Pattern,
             map_in: dict[str, str],
             map_out: dict[str, str | None] | None = None,
@@ -181,7 +178,7 @@ class FlatBuilder(PortList):
             mirrored: tuple[bool, bool] = (False, False),
             inherit_name: bool = True,
             set_rotation: bool | None = None,
-            ) -> BB:
+            ) -> Self:
         """
         Instantiate another pattern into the current device, connecting
           the ports specified by `map_in` and renaming the unconnected
@@ -269,7 +266,7 @@ class FlatBuilder(PortList):
         return self
 
     def place(
-            self: BB,
+            self,
             other: Pattern,
             *,
             offset: ArrayLike = (0, 0),
@@ -278,7 +275,7 @@ class FlatBuilder(PortList):
             mirrored: tuple[bool, bool] = (False, False),
             port_map: dict[str, str | None] | None = None,
             skip_port_check: bool = False,
-            ) -> BB:
+            ) -> Self:
         """
         Instantiate the device `other` into the current device, adding its
           ports to those of the current device (but not connecting any ports).
@@ -348,7 +345,7 @@ class FlatBuilder(PortList):
         self.pattern.append(other_copy)
         return self
 
-    def translate(self: BB, offset: ArrayLike) -> BB:
+    def translate(self, offset: ArrayLike) -> Self:
         """
         Translate the pattern and all ports.
 
@@ -363,7 +360,7 @@ class FlatBuilder(PortList):
             port.translate(offset)
         return self
 
-    def rotate_around(self: BB, pivot: ArrayLike, angle: float) -> BB:
+    def rotate_around(self, pivot: ArrayLike, angle: float) -> Self:
         """
         Rotate the pattern and all ports.
 
@@ -379,7 +376,7 @@ class FlatBuilder(PortList):
             port.rotate_around(pivot, angle)
         return self
 
-    def mirror(self: BB, axis: int) -> BB:
+    def mirror(self, axis: int) -> Self:
         """
         Mirror the pattern and all ports across the specified axis.
 
@@ -394,7 +391,7 @@ class FlatBuilder(PortList):
             p.mirror(axis)
         return self
 
-    def set_dead(self: BB) -> BB:
+    def set_dead(self) -> Self:
         """
         Disallows further changes through `plug()` or `place()`.
         This is meant for debugging:
@@ -417,10 +414,10 @@ class FlatBuilder(PortList):
         return s
 
     def retool(
-            self: BB,
+            self,
             tool: Tool,
             keys: str | Sequence[str | None] | None = None,
-            ) -> BB:
+            ) -> Self:
         if keys is None or isinstance(keys, str):
             self.tools[keys] = tool
         else:
@@ -429,7 +426,7 @@ class FlatBuilder(PortList):
         return self
 
     def path(
-            self: BB,
+            self,
             portspec: str,
             ccw: SupportsBool | None,
             length: float,
@@ -437,7 +434,7 @@ class FlatBuilder(PortList):
             tool_port_names: Sequence[str] = ('A', 'B'),
             base_name: str = '_path',
             **kwargs,
-            ) -> BB:
+            ) -> Self:
         if self._dead:
             logger.error('Skipping path() since device is dead')
             return self
@@ -448,7 +445,7 @@ class FlatBuilder(PortList):
         return self.plug(pat, {portspec: tool_port_names[0]})
 
     def path_to(
-            self: BB,
+            self,
             portspec: str,
             ccw: SupportsBool | None,
             position: float,
@@ -456,7 +453,7 @@ class FlatBuilder(PortList):
             tool_port_names: Sequence[str] = ('A', 'B'),
             base_name: str = '_pathto',
             **kwargs,
-            ) -> BB:
+            ) -> Self:
         if self._dead:
             logger.error('Skipping path_to() since device is dead')
             return self
@@ -482,7 +479,7 @@ class FlatBuilder(PortList):
         return self.path(portspec, ccw, length, tool_port_names=tool_port_names, base_name=base_name, **kwargs)
 
     def mpath(
-            self: BB,
+            self,
             portspec: str | Sequence[str],
             ccw: SupportsBool | None,
             *,
@@ -492,7 +489,7 @@ class FlatBuilder(PortList):
             force_container: bool = False,
             base_name: str = '_mpath',
             **kwargs,
-            ) -> BB:
+            ) -> Self:
         if self._dead:
             logger.error('Skipping mpath() since device is dead')
             return self
diff --git a/masque/label.py b/masque/label.py
index fe34f9b..40b6aba 100644
--- a/masque/label.py
+++ b/masque/label.py
@@ -1,4 +1,4 @@
-from typing import TypeVar
+from typing import Self
 import copy
 
 import numpy
@@ -10,9 +10,6 @@ from .traits import PositionableImpl, LayerableImpl, Copyable, Pivotable, Repeat
 from .traits import AnnotatableImpl
 
 
-L = TypeVar('L', bound='Label')
-
-
 class Label(PositionableImpl, LayerableImpl, RepeatableImpl, AnnotatableImpl,
             Pivotable, Copyable, metaclass=AutoSlots):
     """
@@ -53,7 +50,7 @@ class Label(PositionableImpl, LayerableImpl, RepeatableImpl, AnnotatableImpl,
         self.repetition = repetition
         self.annotations = annotations if annotations is not None else {}
 
-    def __copy__(self: L) -> L:
+    def __copy__(self) -> Self:
         return type(self)(
             string=self.string,
             offset=self.offset.copy(),
@@ -61,13 +58,13 @@ class Label(PositionableImpl, LayerableImpl, RepeatableImpl, AnnotatableImpl,
             repetition=self.repetition,
             )
 
-    def __deepcopy__(self: L, memo: dict | None = None) -> L:
+    def __deepcopy__(self, memo: dict | None = None) -> Self:
         memo = {} if memo is None else memo
         new = copy.copy(self)
         new._offset = self._offset.copy()
         return new
 
-    def rotate_around(self: L, pivot: ArrayLike, rotation: float) -> L:
+    def rotate_around(self, pivot: ArrayLike, rotation: float) -> Self:
         """
         Rotate the label around a point.
 
diff --git a/masque/library.py b/masque/library.py
index 1165140..781983a 100644
--- a/masque/library.py
+++ b/masque/library.py
@@ -5,7 +5,7 @@ Library classes for managing unique name->pattern mappings and
 # TODO documentn all library classes
 # TODO toplevel documentation of library, classes, and abstracts
 """
-from typing import Callable, TypeVar, Type, TYPE_CHECKING, cast
+from typing import Callable, Self, Type, TYPE_CHECKING, cast
 from typing import Iterator, Mapping, MutableMapping, Sequence
 import logging
 import base64
@@ -33,9 +33,6 @@ logger = logging.getLogger(__name__)
 
 
 visitor_function_t = Callable[..., 'Pattern']
-L = TypeVar('L', bound='Library')
-ML = TypeVar('ML', bound='MutableLibrary')
-LL = TypeVar('LL', bound='LazyLibrary')
 
 
 def _rename_patterns(lib: 'Library', name: str) -> str:
@@ -163,10 +160,10 @@ class Library(Mapping[str, 'Pattern'], metaclass=ABCMeta):
         return new
 
     def polygonize(
-            self: L,
+            self,
             num_vertices: int | None = None,
             max_arclen: float | None = None,
-            ) -> L:
+            ) -> Self:
         """
         Calls `.polygonize(...)` on each pattern in this library.
         Arguments are passed on to `shape.to_polygons(...)`.
@@ -186,10 +183,10 @@ class Library(Mapping[str, 'Pattern'], metaclass=ABCMeta):
         return self
 
     def manhattanize(
-            self: L,
+            self,
             grid_x: ArrayLike,
             grid_y: ArrayLike,
-            ) -> L:
+            ) -> Self:
         """
         Calls `.manhattanize(grid_x, grid_y)` on each pattern in this library.
 
@@ -324,7 +321,7 @@ class Library(Mapping[str, 'Pattern'], metaclass=ABCMeta):
         return toplevel
 
     def dfs(
-            self: L,
+            self,
             pattern: 'Pattern',
             visit_before: visitor_function_t | None = None,
             visit_after: visitor_function_t | None = None,
@@ -332,7 +329,7 @@ class Library(Mapping[str, 'Pattern'], metaclass=ABCMeta):
             hierarchy: tuple[str | None, ...] = (None,),
             transform: ArrayLike | bool | None = False,
             memo: dict | None = None,
-            ) -> L:
+            ) -> Self:
         """
         Convenience function.
         Performs a depth-first traversal of a pattern and its referenced patterns.
@@ -454,11 +451,11 @@ class MutableLibrary(Library, MutableMapping[str, 'Pattern'], metaclass=ABCMeta)
         pass
 
     def rename(
-            self: ML,
+            self,
             old_name: str,
             new_name: str,
             move_references: bool = False,
-            ) -> ML:
+            ) -> Self:
         """
         Rename a pattern.
 
@@ -476,7 +473,7 @@ class MutableLibrary(Library, MutableMapping[str, 'Pattern'], metaclass=ABCMeta)
             self.move_references(old_name, new_name)
         return self
 
-    def move_references(self: ML, old_target: str, new_target: str) -> ML:
+    def move_references(self, old_target: str, new_target: str) -> Self:
         """
         Change all references pointing at `old_target` into references pointing at `new_target`.
 
@@ -601,12 +598,12 @@ class MutableLibrary(Library, MutableMapping[str, 'Pattern'], metaclass=ABCMeta)
         return rename_map.get(name, name)
 
     def dedup(
-            self: ML,
+            self,
             norm_value: int = int(1e6),
             exclude_types: tuple[Type] = (Polygon,),
             label2name: Callable[[tuple], str] | None = None,
             threshold: int = 2,
-            ) -> ML:
+            ) -> Self:
         """
         Iterates through all `Pattern`s. Within each `Pattern`, it iterates
          over all shapes, calling `.normalized_form(norm_value)` on them to retrieve a scale-,
@@ -706,9 +703,9 @@ class MutableLibrary(Library, MutableMapping[str, 'Pattern'], metaclass=ABCMeta)
         return self
 
     def wrap_repeated_shapes(
-            self: ML,
+            self,
             name_func: Callable[['Pattern', Shape | Label], str] | None = None,
-            ) -> ML:
+            ) -> Self:
         """
         Wraps all shapes and labels with a non-`None` `repetition` attribute
           into a `Ref`/`Pattern` combination, and applies the `repetition`
@@ -755,9 +752,9 @@ class MutableLibrary(Library, MutableMapping[str, 'Pattern'], metaclass=ABCMeta)
         return self
 
     def subtree(
-            self: ML,
+            self,
             tops: str | Sequence[str],
-            ) -> ML:
+            ) -> Self:
         """
          Return a new `Library`, containing only the specified patterns and the patterns they
         reference (recursively).
@@ -797,10 +794,10 @@ class MutableLibrary(Library, MutableMapping[str, 'Pattern'], metaclass=ABCMeta)
         return trimmed
 
     def delete(
-            self: ML,
+            self,
             key: str,
             delete_refs: bool = True,
-            ) -> ML:
+            ) -> Self:
         # TODO doc delete()
         del self[key]
         if delete_refs:
@@ -961,11 +958,11 @@ class LazyLibrary(MutableLibrary):
         return '<LazyLibrary with keys\n' + pformat(list(self.keys())) + '>'
 
     def rename(
-            self: LL,
+            self,
             old_name: str,
             new_name: str,
             move_references: bool = False,
-            ) -> LL:
+            ) -> Self:
         """
         Rename a pattern.
 
@@ -989,7 +986,7 @@ class LazyLibrary(MutableLibrary):
 
         return self
 
-    def move_references(self: LL, old_target: str, new_target: str) -> LL:
+    def move_references(self, old_target: str, new_target: str) -> Self:
         """
         Change all references pointing at `old_target` into references pointing at `new_target`.
 
@@ -1007,7 +1004,7 @@ class LazyLibrary(MutableLibrary):
                     ref.target = new_target
         return self
 
-    def precache(self: LL) -> LL:
+    def precache(self) -> Self:
         """
         Force all patterns into the cache
 
diff --git a/masque/pattern.py b/masque/pattern.py
index a126bad..e69a66a 100644
--- a/masque/pattern.py
+++ b/masque/pattern.py
@@ -2,7 +2,7 @@
  Base object representing a lithography mask.
 """
 
-from typing import Callable, Sequence, cast, Mapping, TypeVar, Any
+from typing import Callable, Sequence, cast, Mapping, Self, Any
 import copy
 from itertools import chain
 
@@ -20,9 +20,6 @@ from .traits import AnnotatableImpl, Scalable, Mirrorable, Rotatable, Positionab
 from .ports import Port, PortList
 
 
-P = TypeVar('P', bound='Pattern')
-
-
 class Pattern(PortList, AnnotatableImpl, Mirrorable):
     """
     2D layout consisting of some set of shapes, labels, and references to other Pattern objects
@@ -128,7 +125,7 @@ class Pattern(PortList, AnnotatableImpl, Mirrorable):
             )
         return new
 
-    def append(self: P, other_pattern: 'Pattern') -> P:
+    def append(self, other_pattern: 'Pattern') -> Self:
         """
         Appends all shapes, labels and refs from other_pattern to self's shapes,
           labels, and supbatterns.
@@ -212,10 +209,10 @@ class Pattern(PortList, AnnotatableImpl, Mirrorable):
         return pat
 
     def polygonize(
-            self: P,
+            self,
             num_points: int | None = None,
             max_arclen: float | None = None,
-            ) -> P:
+            ) -> Self:
         """
         Calls `.to_polygons(...)` on all the shapes in this Pattern, replacing them with the returned polygons.
         Arguments are passed directly to `shape.to_polygons(...)`.
@@ -237,10 +234,10 @@ class Pattern(PortList, AnnotatableImpl, Mirrorable):
         return self
 
     def manhattanize(
-            self: P,
+            self,
             grid_x: ArrayLike,
             grid_y: ArrayLike,
-            ) -> P:
+            ) -> Self:
         """
         Calls `.polygonize()` on the pattern, then calls `.manhattanize()` on all the
          resulting shapes, replacing them with the returned Manhattan polygons.
@@ -345,7 +342,7 @@ class Pattern(PortList, AnnotatableImpl, Mirrorable):
         assert bounds is not None
         return bounds
 
-    def translate_elements(self: P, offset: ArrayLike) -> P:
+    def translate_elements(self, offset: ArrayLike) -> Self:
         """
         Translates all shapes, label, refs, and ports by the given offset.
 
@@ -359,7 +356,7 @@ class Pattern(PortList, AnnotatableImpl, Mirrorable):
             cast(Positionable, entry).translate(offset)
         return self
 
-    def scale_elements(self: P, c: float) -> P:
+    def scale_elements(self, c: float) -> Self:
         """"
         Scales all shapes and refs by the given value.
 
@@ -373,7 +370,7 @@ class Pattern(PortList, AnnotatableImpl, Mirrorable):
             cast(Scalable, entry).scale_by(c)
         return self
 
-    def scale_by(self: P, c: float) -> P:
+    def scale_by(self, c: float) -> Self:
         """
         Scale this Pattern by the given value
          (all shapes and refs and their offsets are scaled,
@@ -404,7 +401,7 @@ class Pattern(PortList, AnnotatableImpl, Mirrorable):
             port.offset *= c
         return self
 
-    def rotate_around(self: P, pivot: ArrayLike, rotation: float) -> P:
+    def rotate_around(self, pivot: ArrayLike, rotation: float) -> Self:
         """
         Rotate the Pattern around the a location.
 
@@ -422,7 +419,7 @@ class Pattern(PortList, AnnotatableImpl, Mirrorable):
         self.translate_elements(+pivot)
         return self
 
-    def rotate_element_centers(self: P, rotation: float) -> P:
+    def rotate_element_centers(self, rotation: float) -> Self:
         """
         Rotate the offsets of all shapes, labels, refs, and ports around (0, 0)
 
@@ -437,7 +434,7 @@ class Pattern(PortList, AnnotatableImpl, Mirrorable):
             cast(Positionable, entry).offset = numpy.dot(rotation_matrix_2d(rotation), old_offset)
         return self
 
-    def rotate_elements(self: P, rotation: float) -> P:
+    def rotate_elements(self, rotation: float) -> Self:
         """
         Rotate each shape, ref, and port around its origin (offset)
 
@@ -451,7 +448,7 @@ class Pattern(PortList, AnnotatableImpl, Mirrorable):
             cast(Rotatable, entry).rotate(rotation)
         return self
 
-    def mirror_element_centers(self: P, across_axis: int) -> P:
+    def mirror_element_centers(self, across_axis: int) -> Self:
         """
         Mirror the offsets of all shapes, labels, and refs across an axis
 
@@ -466,7 +463,7 @@ class Pattern(PortList, AnnotatableImpl, Mirrorable):
             cast(Positionable, entry).offset[across_axis - 1] *= -1
         return self
 
-    def mirror_elements(self: P, across_axis: int) -> P:
+    def mirror_elements(self, across_axis: int) -> Self:
         """
         Mirror each shape, ref, and pattern across an axis, relative
           to its offset
@@ -482,7 +479,7 @@ class Pattern(PortList, AnnotatableImpl, Mirrorable):
             cast(Mirrorable, entry).mirror(across_axis)
         return self
 
-    def mirror(self: P, across_axis: int) -> P:
+    def mirror(self, across_axis: int) -> Self:
         """
         Mirror the Pattern across an axis
 
@@ -497,7 +494,7 @@ class Pattern(PortList, AnnotatableImpl, Mirrorable):
         self.mirror_element_centers(across_axis)
         return self
 
-    def copy(self: P) -> P:
+    def copy(self) -> Self:
         """
         Return a copy of the Pattern, deep-copying shapes and copying refs
          entries, but not deep-copying any referenced patterns.
@@ -509,7 +506,7 @@ class Pattern(PortList, AnnotatableImpl, Mirrorable):
         """
         return copy.copy(self)
 
-    def deepcopy(self: P) -> P:
+    def deepcopy(self) -> Self:
         """
         Convenience method for `copy.deepcopy(pattern)`
 
@@ -528,7 +525,7 @@ class Pattern(PortList, AnnotatableImpl, Mirrorable):
                 and len(self.shapes) == 0
                 and len(self.labels) == 0)
 
-    def ref(self: P, *args: Any, **kwargs: Any) -> P:
+    def ref(self, *args: Any, **kwargs: Any) -> Self:
         """
         Convenience function which constructs a `Ref` object and adds it
          to this pattern.
@@ -543,7 +540,7 @@ class Pattern(PortList, AnnotatableImpl, Mirrorable):
         self.refs.append(Ref(*args, **kwargs))
         return self
 
-    def rect(self: P, *args: Any, **kwargs: Any) -> P:
+    def rect(self, *args: Any, **kwargs: Any) -> Self:
         """
         Convenience function which calls `Polygon.rect` to construct a
          rectangle and adds it to this pattern.
@@ -559,8 +556,8 @@ class Pattern(PortList, AnnotatableImpl, Mirrorable):
         return self
 
     def flatten(
-            self: P,
-            library: Mapping[str, P],
+            self,
+            library: Mapping[str, 'Pattern'],
             flatten_ports: bool = False,       # TODO document
             ) -> 'Pattern':
         """
@@ -573,7 +570,7 @@ class Pattern(PortList, AnnotatableImpl, Mirrorable):
         Returns:
             self
         """
-        flattened: dict[str | None, P | None] = {}
+        flattened: dict[str | None, 'Pattern' | None] = {}
 
         # TODO both Library and Pattern have flatten()... pattern is in-place?
         def flatten_single(name: str | None) -> None:
@@ -609,8 +606,8 @@ class Pattern(PortList, AnnotatableImpl, Mirrorable):
         return self
 
     def visualize(
-            self: P,
-            library: Mapping[str, P] | None = None,
+            self,
+            library: Mapping[str, 'Pattern'] | None = None,
             offset: ArrayLike = (0., 0.),
             line_color: str = 'k',
             fill_color: str = 'none',
diff --git a/masque/ports.py b/masque/ports.py
index 85ca750..36c47c4 100644
--- a/masque/ports.py
+++ b/masque/ports.py
@@ -1,4 +1,4 @@
-from typing import Iterable, KeysView, ValuesView, overload, TypeVar
+from typing import Iterable, KeysView, ValuesView, overload, Self
 import warnings
 import traceback
 import logging
@@ -17,11 +17,6 @@ from .error import PortError
 logger = logging.getLogger(__name__)
 
 
-P = TypeVar('P', bound='Port')
-PL  = TypeVar('PL',  bound='PortList')
-PL2 = TypeVar('PL2', bound='PortList')
-
-
 class Port(PositionableImpl, Rotatable, PivotableImpl, Copyable, Mirrorable):
     """
     A point at which a `Device` can be snapped to another `Device`.
@@ -76,24 +71,24 @@ class Port(PositionableImpl, Rotatable, PivotableImpl, Copyable, Mirrorable):
     def get_bounds(self):
         return numpy.vstack((self.offset, self.offset))
 
-    def set_ptype(self: P, ptype: str) -> P:
+    def set_ptype(self, ptype: str) -> Self:
         """ Chainable setter for `ptype` """
         self.ptype = ptype
         return self
 
-    def mirror(self: P, axis: int) -> P:
+    def mirror(self, axis: int) -> Self:
         self.offset[1 - axis] *= -1
         if self.rotation is not None:
             self.rotation *= -1
             self.rotation += axis * pi
         return self
 
-    def rotate(self: P, rotation: float) -> P:
+    def rotate(self, rotation: float) -> Self:
         if self.rotation is not None:
             self.rotation += rotation
         return self
 
-    def set_rotation(self: P, rotation: float | None) -> P:
+    def set_rotation(self, rotation: float | None) -> Self:
         self.rotation = rotation
         return self
 
@@ -148,10 +143,10 @@ class PortList(metaclass=ABCMeta):
     # and because you can just grab .ports and use that instead
 
     def rename_ports(
-            self: PL,
+            self,
             mapping: dict[str, str | None],
             overwrite: bool = False,
-            ) -> PL:
+            ) -> Self:
         """
         Renames ports as specified by `mapping`.
         Ports can be explicitly deleted by mapping them to `None`.
@@ -179,12 +174,12 @@ class PortList(metaclass=ABCMeta):
         return self
 
     def add_port_pair(
-            self: PL,
+            self,
             offset: ArrayLike = (0, 0),
             rotation: float = 0.0,
             names: tuple[str, str] = ('A', 'B'),
             ptype: str = 'unk',
-            ) -> PL:
+            ) -> Self:
         """
         Add a pair of ports with opposing directions at the specified location.
 
@@ -207,11 +202,11 @@ class PortList(metaclass=ABCMeta):
         return self
 
     def check_ports(
-            self: PL,
+            self,
             other_names: Iterable[str],
             map_in: dict[str, str] | None = None,
             map_out: dict[str, str | None] | None = None,
-            ) -> PL:
+            ) -> Self:
         """
         Given the provided port mappings, check that:
             - All of the ports specified in the mappings exist
@@ -276,8 +271,8 @@ class PortList(metaclass=ABCMeta):
         return self
 
     def find_transform(
-            self: PL,
-            other: PL2,
+            self,
+            other: 'PortList',
             map_in: dict[str, str],
             *,
             mirrored: tuple[bool, bool] = (False, False),
diff --git a/masque/ref.py b/masque/ref.py
index ddd2245..17fddb1 100644
--- a/masque/ref.py
+++ b/masque/ref.py
@@ -4,7 +4,7 @@
 """
 #TODO more top-level documentation
 
-from typing import Sequence, Mapping, TYPE_CHECKING, Any, TypeVar, cast
+from typing import Sequence, Mapping, TYPE_CHECKING, Any, Self, cast
 import copy
 
 import numpy
@@ -24,9 +24,6 @@ if TYPE_CHECKING:
     from . import Pattern, NamedPattern
 
 
-R = TypeVar('R', bound='Ref')
-
-
 class Ref(
         PositionableImpl, RotatableImpl, ScalableImpl, Mirrorable,
         PivotableImpl, Copyable, RepeatableImpl, AnnotatableImpl,
@@ -164,13 +161,13 @@ class Ref(
 
         return pattern
 
-    def rotate(self: R, rotation: float) -> R:
+    def rotate(self, rotation: float) -> Self:
         self.rotation += rotation
         if self.repetition is not None:
             self.repetition.rotate(rotation)
         return self
 
-    def mirror(self: R, axis: int) -> R:
+    def mirror(self, axis: int) -> Self:
         self.mirrored[axis] = not self.mirrored[axis]
         self.rotation *= -1
         if self.repetition is not None:
diff --git a/masque/shapes/shape.py b/masque/shapes/shape.py
index 201fc2b..362be57 100644
--- a/masque/shapes/shape.py
+++ b/masque/shapes/shape.py
@@ -1,4 +1,4 @@
-from typing import Callable, TypeVar, TYPE_CHECKING
+from typing import Callable, Self, TYPE_CHECKING
 from abc import ABCMeta, abstractmethod
 
 import numpy
@@ -26,9 +26,6 @@ normalized_shape_tuple = tuple[
 DEFAULT_POLY_NUM_VERTICES = 24
 
 
-T = TypeVar('T', bound='Shape')
-
-
 class Shape(PositionableImpl, LayerableImpl, Rotatable, Mirrorable, Copyable, Scalable,
             PivotableImpl, RepeatableImpl, AnnotatableImpl, metaclass=ABCMeta):
     """
@@ -68,7 +65,7 @@ class Shape(PositionableImpl, LayerableImpl, Rotatable, Mirrorable, Copyable, Sc
         pass
 
     @abstractmethod
-    def normalized_form(self: T, norm_value: int) -> normalized_shape_tuple:
+    def normalized_form(self, norm_value: int) -> normalized_shape_tuple:
         """
         Writes the shape in a standardized notation, with offset, scale, and rotation
          information separated out from the remaining values.
diff --git a/masque/traits/annotatable.py b/masque/traits/annotatable.py
index b10b042..e36ceee 100644
--- a/masque/traits/annotatable.py
+++ b/masque/traits/annotatable.py
@@ -1,4 +1,4 @@
-from typing import TypeVar
+from typing import Self
 #from types import MappingProxyType
 from abc import ABCMeta, abstractmethod
 
@@ -9,10 +9,6 @@ from ..error import MasqueError
 _empty_slots = ()     # Workaround to get mypy to ignore intentionally empty slots for superclass
 
 
-T = TypeVar('T', bound='Annotatable')
-I = TypeVar('I', bound='AnnotatableImpl')
-
-
 class Annotatable(metaclass=ABCMeta):
     """
     Abstract class for all annotatable entities
diff --git a/masque/traits/copyable.py b/masque/traits/copyable.py
index aa84356..76cd26d 100644
--- a/masque/traits/copyable.py
+++ b/masque/traits/copyable.py
@@ -1,11 +1,8 @@
-from typing import TypeVar
+from typing import Self
 from abc import ABCMeta
 import copy
 
 
-T = TypeVar('T', bound='Copyable')
-
-
 class Copyable(metaclass=ABCMeta):
     """
     Abstract class which adds .copy() and .deepcopy()
@@ -15,7 +12,7 @@ class Copyable(metaclass=ABCMeta):
     '''
     ---- Non-abstract methods
     '''
-    def copy(self: T) -> T:
+    def copy(self) -> Self:
         """
         Return a shallow copy of the object.
 
@@ -24,7 +21,7 @@ class Copyable(metaclass=ABCMeta):
         """
         return copy.copy(self)
 
-    def deepcopy(self: T) -> T:
+    def deepcopy(self) -> Self:
         """
         Return a deep copy of the object.
 
diff --git a/masque/traits/layerable.py b/masque/traits/layerable.py
index eae2de4..29d9653 100644
--- a/masque/traits/layerable.py
+++ b/masque/traits/layerable.py
@@ -1,4 +1,4 @@
-from typing import TypeVar
+from typing import Self
 from abc import ABCMeta, abstractmethod
 
 from ..utils import layer_t
@@ -7,10 +7,6 @@ from ..utils import layer_t
 _empty_slots = ()     # Workaround to get mypy to ignore intentionally empty slots for superclass
 
 
-T = TypeVar('T', bound='Layerable')
-I = TypeVar('I', bound='LayerableImpl')
-
-
 class Layerable(metaclass=ABCMeta):
     """
     Abstract class for all layerable entities
@@ -36,7 +32,7 @@ class Layerable(metaclass=ABCMeta):
     ---- Methods
     '''
     @abstractmethod
-    def set_layer(self: T, layer: layer_t) -> T:
+    def set_layer(self, layer: layer_t) -> Self:
         """
         Set the layer
 
@@ -72,6 +68,6 @@ class LayerableImpl(Layerable, metaclass=ABCMeta):
     '''
     ---- Non-abstract methods
     '''
-    def set_layer(self: I, layer: layer_t) -> I:
+    def set_layer(self, layer: layer_t) -> Self:
         self.layer = layer
         return self
diff --git a/masque/traits/mirrorable.py b/masque/traits/mirrorable.py
index bc82b83..5bbbad4 100644
--- a/masque/traits/mirrorable.py
+++ b/masque/traits/mirrorable.py
@@ -1,11 +1,7 @@
-from typing import TypeVar
+from typing import Self
 from abc import ABCMeta, abstractmethod
 
 
-T = TypeVar('T', bound='Mirrorable')
-#I = TypeVar('I', bound='MirrorableImpl')
-
-
 class Mirrorable(metaclass=ABCMeta):
     """
     Abstract class for all mirrorable entities
@@ -16,7 +12,7 @@ class Mirrorable(metaclass=ABCMeta):
     ---- Abstract methods
     '''
     @abstractmethod
-    def mirror(self: T, axis: int) -> T:
+    def mirror(self, axis: int) -> Self:
         """
         Mirror the entity across an axis.
 
@@ -28,7 +24,7 @@ class Mirrorable(metaclass=ABCMeta):
         """
         pass
 
-    def mirror2d(self: T, axes: tuple[bool, bool]) -> T:
+    def mirror2d(self, axes: tuple[bool, bool]) -> Self:
         """
         Optionally mirror the entity across both axes
 
diff --git a/masque/traits/positionable.py b/masque/traits/positionable.py
index 1f4ba6e..ba25cc0 100644
--- a/masque/traits/positionable.py
+++ b/masque/traits/positionable.py
@@ -1,6 +1,6 @@
 # TODO top-level comment about how traits should set __slots__ = (), and how to use AutoSlots
 
-from typing import TypeVar, Any
+from typing import Self, Any
 from abc import ABCMeta, abstractmethod
 
 import numpy
@@ -12,10 +12,6 @@ from ..error import MasqueError
 _empty_slots = ()     # Workaround to get mypy to ignore intentionally empty slots for superclass
 
 
-T = TypeVar('T', bound='Positionable')
-I = TypeVar('I', bound='PositionableImpl')
-
-
 class Positionable(metaclass=ABCMeta):
     """
     Abstract class for all positionable entities
@@ -39,7 +35,7 @@ class Positionable(metaclass=ABCMeta):
         pass
 
     @abstractmethod
-    def set_offset(self: T, offset: ArrayLike) -> T:
+    def set_offset(self, offset: ArrayLike) -> Self:
         """
         Set the offset
 
@@ -52,7 +48,7 @@ class Positionable(metaclass=ABCMeta):
         pass
 
     @abstractmethod
-    def translate(self: T, offset: ArrayLike) -> T:
+    def translate(self, offset: ArrayLike) -> Self:
         """
         Translate the entity by the given offset
 
@@ -116,10 +112,10 @@ class PositionableImpl(Positionable, metaclass=ABCMeta):
     '''
     ---- Methods
     '''
-    def set_offset(self: I, offset: ArrayLike) -> I:
+    def set_offset(self, offset: ArrayLike) -> Self:
         self.offset = offset
         return self
 
-    def translate(self: I, offset: ArrayLike) -> I:
+    def translate(self, offset: ArrayLike) -> Self:
         self._offset += offset   # type: ignore         # NDArray += ArrayLike should be fine??
         return self
diff --git a/masque/traits/repeatable.py b/masque/traits/repeatable.py
index f9f6438..7be1559 100644
--- a/masque/traits/repeatable.py
+++ b/masque/traits/repeatable.py
@@ -1,4 +1,4 @@
-from typing import TypeVar, TYPE_CHECKING
+from typing import Self, TYPE_CHECKING
 from abc import ABCMeta, abstractmethod
 
 from ..error import MasqueError
@@ -11,10 +11,6 @@ if TYPE_CHECKING:
     from ..repetition import Repetition
 
 
-T = TypeVar('T', bound='Repeatable')
-I = TypeVar('I', bound='RepeatableImpl')
-
-
 class Repeatable(metaclass=ABCMeta):
     """
     Abstract class for all repeatable entities
@@ -41,7 +37,7 @@ class Repeatable(metaclass=ABCMeta):
     ---- Methods
     '''
     @abstractmethod
-    def set_repetition(self: T, repetition: 'Repetition' | None) -> T:
+    def set_repetition(self, repetition: 'Repetition' | None) -> Self:
         """
         Set the repetition
 
@@ -80,6 +76,6 @@ class RepeatableImpl(Repeatable, metaclass=ABCMeta):
     '''
     ---- Non-abstract methods
     '''
-    def set_repetition(self: I, repetition: 'Repetition' | None) -> I:
+    def set_repetition(self, repetition: 'Repetition' | None) -> Self:
         self.repetition = repetition
         return self
diff --git a/masque/traits/rotatable.py b/masque/traits/rotatable.py
index b9bfab2..0e06527 100644
--- a/masque/traits/rotatable.py
+++ b/masque/traits/rotatable.py
@@ -1,4 +1,4 @@
-from typing import TypeVar, cast, Any
+from typing import Self, cast, Any
 from abc import ABCMeta, abstractmethod
 
 import numpy
@@ -13,12 +13,6 @@ from ..utils import rotation_matrix_2d
 _empty_slots = ()     # Workaround to get mypy to ignore intentionally empty slots for superclass
 
 
-T = TypeVar('T', bound='Rotatable')
-I = TypeVar('I', bound='RotatableImpl')
-P = TypeVar('P', bound='Pivotable')
-J = TypeVar('J', bound='PivotableImpl')
-
-
 class Rotatable(metaclass=ABCMeta):
     """
     Abstract class for all rotatable entities
@@ -29,7 +23,7 @@ class Rotatable(metaclass=ABCMeta):
     ---- Abstract methods
     '''
     @abstractmethod
-    def rotate(self: T, val: float) -> T:
+    def rotate(self, val: float) -> Self:
         """
         Rotate the shape around its origin (0, 0), ignoring its offset.
 
@@ -68,11 +62,11 @@ class RotatableImpl(Rotatable, metaclass=ABCMeta):
     '''
     ---- Methods
     '''
-    def rotate(self: I, rotation: float) -> I:
+    def rotate(self, rotation: float) -> Self:
         self.rotation += rotation
         return self
 
-    def set_rotation(self: I, rotation: float) -> I:
+    def set_rotation(self, rotation: float) -> Self:
         """
         Set the rotation to a value
 
@@ -94,7 +88,7 @@ class Pivotable(metaclass=ABCMeta):
     __slots__ = ()
 
     @abstractmethod
-    def rotate_around(self: P, pivot: ArrayLike, rotation: float) -> P:
+    def rotate_around(self, pivot: ArrayLike, rotation: float) -> Self:
         """
         Rotate the object around a point.
 
@@ -117,7 +111,7 @@ class PivotableImpl(Pivotable, metaclass=ABCMeta):
     offset: Any         # TODO see if we can get around defining `offset` in  PivotableImpl
     """ `[x_offset, y_offset]` """
 
-    def rotate_around(self: J, pivot: ArrayLike, rotation: float) -> J:
+    def rotate_around(self, pivot: ArrayLike, rotation: float) -> Self:
         pivot = numpy.array(pivot, dtype=float)
         cast(Positionable, self).translate(-pivot)
         cast(Rotatable, self).rotate(rotation)
diff --git a/masque/traits/scalable.py b/masque/traits/scalable.py
index 2216945..2869aef 100644
--- a/masque/traits/scalable.py
+++ b/masque/traits/scalable.py
@@ -1,4 +1,4 @@
-from typing import TypeVar
+from typing import Self
 from abc import ABCMeta, abstractmethod
 
 from ..error import MasqueError
@@ -8,10 +8,6 @@ from ..utils import is_scalar
 _empty_slots = ()     # Workaround to get mypy to ignore intentionally empty slots for superclass
 
 
-T = TypeVar('T', bound='Scalable')
-I = TypeVar('I', bound='ScalableImpl')
-
-
 class Scalable(metaclass=ABCMeta):
     """
     Abstract class for all scalable entities
@@ -22,7 +18,7 @@ class Scalable(metaclass=ABCMeta):
     ---- Abstract methods
     '''
     @abstractmethod
-    def scale_by(self: T, c: float) -> T:
+    def scale_by(self, c: float) -> Self:
         """
         Scale the entity by a factor
 
@@ -62,11 +58,11 @@ class ScalableImpl(Scalable, metaclass=ABCMeta):
     '''
     ---- Methods
     '''
-    def scale_by(self: I, c: float) -> I:
+    def scale_by(self, c: float) -> Self:
         self.scale *= c
         return self
 
-    def set_scale(self: I, scale: float) -> I:
+    def set_scale(self, scale: float) -> Self:
         """
         Set the sclae to a value