diff --git a/examples/tutorial/devices.py b/examples/tutorial/devices.py
index 46fcd27..45b4a36 100644
--- a/examples/tutorial/devices.py
+++ b/examples/tutorial/devices.py
@@ -8,7 +8,7 @@ from masque import (
     layer_t, Pattern, Ref, Label, Builder, Port, Polygon,
     WrapLibrary, Library,
     )
-from masque.builder import port_utils
+from masque.utils import ports2data
 from masque.file.gdsii import writefile, check_valid_names
 
 import pcgen
@@ -20,20 +20,20 @@ LATTICE_CONSTANT = 512
 RADIUS = LATTICE_CONSTANT / 2 * 0.75
 
 
-def dev2pat(dev: Pattern) -> Pattern:
+def ports_to_data(pat: Pattern) -> Pattern:
     """
     Bake port information into the pattern.
     This places a label at each port location on layer (3, 0) with text content
       'name:ptype angle_deg'
     """
-    return port_utils.dev2pat(dev, layer=(3, 0))
+    return ports2data.ports_to_data(pat, layer=(3, 0))
 
 
-def pat2dev(lib: Mapping[str, Pattern], name: str, pat: Pattern) -> Pattern:
+def data_to_ports(lib: Mapping[str, Pattern], name: str, pat: Pattern) -> Pattern:
     """
-    Scans the Pattern to determine port locations. Same format as `dev2pat`
+    Scans the Pattern to determine port locations. Same port format as `ports_to_data`
     """
-    return port_utils.pat2dev(layers=[(3, 0)], library=lib, pattern=pat, name=name)
+    return ports2data.data_to_ports(layers=[(3, 0)], library=lib, pattern=pat, name=name)
 
 
 def perturbed_l3(
@@ -103,7 +103,7 @@ def perturbed_l3(
         output=Port((extent, 0), rotation=pi, ptype='pcwg'),
         )
 
-    dev2pat(pat)
+    ports_to_data(pat)
     return pat
 
 
@@ -142,8 +142,8 @@ def waveguide(
         left=Port((-extent, 0), rotation=0, ptype='pcwg'),
         right=Port((extent, 0), rotation=pi, ptype='pcwg'),
         )
-    dev2pat(pat)
-    print(pat)
+
+    ports_to_data(pat)
     return pat
 
 
@@ -183,7 +183,7 @@ def bend(
                     extent * numpy.sqrt(3) / 2),
                    rotation=pi * 4 / 3, ptype='pcwg'),
         )
-    dev2pat(pat)
+    ports_to_data(pat)
     return pat
 
 
@@ -222,7 +222,7 @@ def y_splitter(
         'bot': Port((extent / 2, -extent * numpy.sqrt(3) / 2), rotation=pi * 2 / 3, ptype='pcwg'),
         }
 
-    dev2pat(pat)
+    ports_to_data(pat)
     return pat
 
 
@@ -311,7 +311,7 @@ def main(interactive: bool = True) -> None:
     # We can also add text labels for our circuit's ports.
     #   They will appear at the uppermost hierarchy level, while the individual
     # device ports will appear further down, in their respective cells.
-    dev2pat(circ.pattern)
+    ports_to_data(circ.pattern)
 
     # Add the pattern into our library
     lib['my_circuit'] = circ.pattern
diff --git a/examples/tutorial/library.py b/examples/tutorial/library.py
index 25c8851..b86a81c 100644
--- a/examples/tutorial/library.py
+++ b/examples/tutorial/library.py
@@ -10,7 +10,7 @@ from masque.file.gdsii import writefile, load_libraryfile
 import pcgen
 import basic_shapes
 import devices
-from devices import pat2dev, dev2pat
+from devices import ports_to_data, data_to_ports
 from basic_shapes import GDS_OPTS
 
 
@@ -24,7 +24,7 @@ def main() -> None:
     #
 
     # Scan circuit.gds and prepare to lazy-load its contents
-    gds_lib, _properties = load_libraryfile('circuit.gds', postprocess=pat2dev)
+    gds_lib, _properties = load_libraryfile('circuit.gds', postprocess=data_to_ports)
 
     # Add it into the device library by providing a way to read port info
     #   This maintains the lazy evaluation from above, so no patterns
@@ -59,13 +59,18 @@ def main() -> None:
     # Immediately start building from an instance of the L3 cavity
     circ2 = Builder(library=lib, ports='tri_l3cav')
 
-    print(lib['wg10'].ports)
+    #   First way to get abstracts is `lib.abstract(name)`
     circ2.plug(lib.abstract('wg10'), {'input': 'right'})
 
-    abstracts = lib.abstract_view()     # Alternate way to get abstracts
+    #   Second way to get abstracts is to use an AbstractView
+    abstracts = lib.abstract_view()
     circ2.plug(abstracts['wg10'], {'output': 'left'})
-    circ2.plug(abstracts['tri_wg10'], {'input': 'right'})
-    circ2.plug(abstracts['tri_wg10'], {'output': 'left'})
+
+    # Third way to specify an abstract works by automatically getting
+    # it from the library already within the Builder object:
+    # Just pass the pattern name!
+    circ2.plug('tri_wg10', {'input': 'right'})
+    circ2.plug('tri_wg10', {'output': 'left'})
 
     # Add the circuit to the device library.
     #  It has already been generated, so we can use `set_const` as a shorthand for
@@ -81,15 +86,15 @@ def main() -> None:
     circ3 = Builder.interface(source=circ2)
 
     # ... that lets us continue from where we left off.
-    circ3.plug(abstracts['tri_bend0'], {'input': 'right'})
-    circ3.plug(abstracts['tri_bend0'], {'input': 'left'}, mirrored=(True, False)) # mirror since no tri y-symmetry
-    circ3.plug(abstracts['tri_bend0'], {'input': 'right'})
-    circ3.plug(abstracts['bend0'], {'output': 'left'})
-    circ3.plug(abstracts['bend0'], {'output': 'left'})
-    circ3.plug(abstracts['bend0'], {'output': 'left'})
-    circ3.plug(abstracts['tri_wg10'], {'input': 'right'})
-    circ3.plug(abstracts['tri_wg28'], {'input': 'right'})
-    circ3.plug(abstracts['tri_wg10'], {'input': 'right', 'output': 'left'})
+    circ3.plug('tri_bend0', {'input': 'right'})
+    circ3.plug('tri_bend0', {'input': 'left'}, mirrored=(True, False)) # mirror since no tri y-symmetry
+    circ3.plug('tri_bend0', {'input': 'right'})
+    circ3.plug('bend0', {'output': 'left'})
+    circ3.plug('bend0', {'output': 'left'})
+    circ3.plug('bend0', {'output': 'left'})
+    circ3.plug('tri_wg10', {'input': 'right'})
+    circ3.plug('tri_wg28', {'input': 'right'})
+    circ3.plug('tri_wg10', {'input': 'right', 'output': 'left'})
 
     lib.set_const('loop_segment', circ3.pattern)
 
diff --git a/masque/__init__.py b/masque/__init__.py
index c2f0f6d..3914ee4 100644
--- a/masque/__init__.py
+++ b/masque/__init__.py
@@ -27,12 +27,13 @@
 
 """
 
+from .utils import layer_t, annotations_t, SupportsBool
 from .error import MasqueError, PatternError, LibraryError, BuildError
 from .shapes import Shape, Polygon, Path, Circle, Arc, Ellipse
 from .label import Label
 from .ref import Ref
 from .pattern import Pattern
-from .utils import layer_t, annotations_t
+
 from .library import Library, MutableLibrary, WrapROLibrary, WrapLibrary, LazyLibrary, AbstractView
 from .ports import Port, PortList
 from .abstract import Abstract
diff --git a/masque/repetition.py b/masque/repetition.py
index 5f0d8b0..467783c 100644
--- a/masque/repetition.py
+++ b/masque/repetition.py
@@ -10,16 +10,16 @@ from abc import ABCMeta, abstractmethod
 import numpy
 from numpy.typing import ArrayLike, NDArray
 
-from .error import PatternError
-from .utils import rotation_matrix_2d, AutoSlots
 from .traits import Copyable, Scalable, Rotatable, Mirrorable
+from .error import PatternError
+from .utils import rotation_matrix_2d
 
 
 class Repetition(Copyable, Rotatable, Mirrorable, Scalable, metaclass=ABCMeta):
     """
     Interface common to all objects which specify repetitions
     """
-    __slots__ = ()
+    __slots__ = ()      # Allow subclasses to use __slots__
 
     @property
     @abstractmethod
@@ -30,7 +30,7 @@ class Repetition(Copyable, Rotatable, Mirrorable, Scalable, metaclass=ABCMeta):
         pass
 
 
-class Grid(Repetition, metaclass=AutoSlots):
+class Grid(Repetition):
     """
     `Grid` describes a 2D grid formed by two basis vectors and two 'counts' (sizes).
 
@@ -279,7 +279,7 @@ class Grid(Repetition, metaclass=AutoSlots):
         return True
 
 
-class Arbitrary(Repetition, metaclass=AutoSlots):
+class Arbitrary(Repetition):
     """
     `Arbitrary` is a simple list of (absolute) displacements for instances.
 
diff --git a/masque/shapes/arc.py b/masque/shapes/arc.py
index d254afc..3e6e8bd 100644
--- a/masque/shapes/arc.py
+++ b/masque/shapes/arc.py
@@ -7,12 +7,12 @@ from numpy import pi
 from numpy.typing import NDArray, ArrayLike
 
 from . import Shape, Polygon, normalized_shape_tuple, DEFAULT_POLY_NUM_POINTS
-from .. import PatternError
+from ..error import PatternError
 from ..repetition import Repetition
-from ..utils import is_scalar, layer_t, AutoSlots, annotations_t
+from ..utils import is_scalar, layer_t, annotations_t
 
 
-class Arc(Shape, metaclass=AutoSlots):
+class Arc(Shape):
     """
     An elliptical arc, formed by cutting off an elliptical ring with two rays which exit from its
      center. It has a position, two radii, a start and stop angle, a rotation, and a width.
diff --git a/masque/shapes/circle.py b/masque/shapes/circle.py
index 017f4bb..545c459 100644
--- a/masque/shapes/circle.py
+++ b/masque/shapes/circle.py
@@ -6,12 +6,12 @@ from numpy import pi
 from numpy.typing import NDArray, ArrayLike
 
 from . import Shape, Polygon, normalized_shape_tuple, DEFAULT_POLY_NUM_POINTS
-from .. import PatternError
+from ..error import PatternError
 from ..repetition import Repetition
-from ..utils import is_scalar, layer_t, AutoSlots, annotations_t
+from ..utils import is_scalar, layer_t, annotations_t
 
 
-class Circle(Shape, metaclass=AutoSlots):
+class Circle(Shape):
     """
     A circle, which has a position and radius.
     """
diff --git a/masque/shapes/ellipse.py b/masque/shapes/ellipse.py
index 32f79fd..6b39225 100644
--- a/masque/shapes/ellipse.py
+++ b/masque/shapes/ellipse.py
@@ -7,12 +7,12 @@ from numpy import pi
 from numpy.typing import ArrayLike, NDArray
 
 from . import Shape, Polygon, normalized_shape_tuple, DEFAULT_POLY_NUM_POINTS
-from .. import PatternError
+from ..error import PatternError
 from ..repetition import Repetition
-from ..utils import is_scalar, rotation_matrix_2d, layer_t, AutoSlots, annotations_t
+from ..utils import is_scalar, rotation_matrix_2d, layer_t, annotations_t
 
 
-class Ellipse(Shape, metaclass=AutoSlots):
+class Ellipse(Shape):
     """
     An ellipse, which has a position, two radii, and a rotation.
     The rotation gives the angle from x-axis, counterclockwise, to the first (x) radius.
diff --git a/masque/shapes/path.py b/masque/shapes/path.py
index 0b826a6..628e2ab 100644
--- a/masque/shapes/path.py
+++ b/masque/shapes/path.py
@@ -7,9 +7,9 @@ from numpy import pi, inf
 from numpy.typing import NDArray, ArrayLike
 
 from . import Shape, normalized_shape_tuple, Polygon, Circle
-from .. import PatternError
+from ..error import PatternError
 from ..repetition import Repetition
-from ..utils import is_scalar, rotation_matrix_2d, layer_t, AutoSlots
+from ..utils import is_scalar, rotation_matrix_2d, layer_t
 from ..utils import remove_colinear_vertices, remove_duplicate_vertices, annotations_t
 
 
@@ -21,7 +21,7 @@ class PathCap(Enum):
 #                     #     defined by path.cap_extensions
 
 
-class Path(Shape, metaclass=AutoSlots):
+class Path(Shape):
     """
     A path, consisting of a bunch of vertices (Nx2 ndarray), a width, an end-cap shape,
         and an offset.
diff --git a/masque/shapes/polygon.py b/masque/shapes/polygon.py
index acdd9f5..8eade70 100644
--- a/masque/shapes/polygon.py
+++ b/masque/shapes/polygon.py
@@ -6,13 +6,13 @@ from numpy import pi
 from numpy.typing import NDArray, ArrayLike
 
 from . import Shape, normalized_shape_tuple
-from .. import PatternError
+from ..error import PatternError
 from ..repetition import Repetition
-from ..utils import is_scalar, rotation_matrix_2d, layer_t, AutoSlots
+from ..utils import is_scalar, rotation_matrix_2d, layer_t
 from ..utils import remove_colinear_vertices, remove_duplicate_vertices, annotations_t
 
 
-class Polygon(Shape, metaclass=AutoSlots):
+class Polygon(Shape):
     """
     A polygon, consisting of a bunch of vertices (Nx2 ndarray) which specify an
        implicitly-closed boundary, and an offset.
diff --git a/masque/shapes/text.py b/masque/shapes/text.py
index d70e477..62ef960 100644
--- a/masque/shapes/text.py
+++ b/masque/shapes/text.py
@@ -6,10 +6,10 @@ from numpy import pi, inf
 from numpy.typing import NDArray, ArrayLike
 
 from . import Shape, Polygon, normalized_shape_tuple
-from .. import PatternError
+from ..error import PatternError
 from ..repetition import Repetition
 from ..traits import RotatableImpl
-from ..utils import is_scalar, get_bit, normalize_mirror, layer_t, AutoSlots
+from ..utils import is_scalar, get_bit, normalize_mirror, layer_t
 from ..utils import annotations_t
 
 # Loaded on use:
@@ -17,7 +17,7 @@ from ..utils import annotations_t
 # from matplotlib.path import Path
 
 
-class Text(RotatableImpl, Shape, metaclass=AutoSlots):
+class Text(RotatableImpl, Shape):
     """
     Text (to be printed e.g. as a set of polygons).
     This is distinct from non-printed Label objects.
diff --git a/masque/traits/positionable.py b/masque/traits/positionable.py
index 593ae46..8e25b9c 100644
--- a/masque/traits/positionable.py
+++ b/masque/traits/positionable.py
@@ -35,7 +35,7 @@ class Positionable(metaclass=ABCMeta):
 
     @offset.setter
     @abstractmethod
-    def offset(self, val: ArrayLike):
+    def offset(self, val: ArrayLike) -> None:
         pass
 
     @abstractmethod
diff --git a/masque/traits/rotatable.py b/masque/traits/rotatable.py
index 07fb440..b9bfab2 100644
--- a/masque/traits/rotatable.py
+++ b/masque/traits/rotatable.py
@@ -1,4 +1,4 @@
-from typing import TypeVar, cast
+from typing import TypeVar, cast, Any
 from abc import ABCMeta, abstractmethod
 
 import numpy
@@ -114,6 +114,9 @@ class PivotableImpl(Pivotable, metaclass=ABCMeta):
     """
     __slots__ = ()
 
+    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:
         pivot = numpy.array(pivot, dtype=float)
         cast(Positionable, self).translate(-pivot)
diff --git a/masque/utils/__init__.py b/masque/utils/__init__.py
index 3afd6f1..1e04a35 100644
--- a/masque/utils/__init__.py
+++ b/masque/utils/__init__.py
@@ -2,7 +2,6 @@
 Various helper functions, type definitions, etc.
 """
 from .types import layer_t, annotations_t, SupportsBool
-
 from .array import is_scalar
 from .autoslots import AutoSlots
 from .deferreddict import DeferredDict