diff --git a/masque/builder/utils.py b/masque/builder/utils.py
index fe30cf4..c466c71 100644
--- a/masque/builder/utils.py
+++ b/masque/builder/utils.py
@@ -202,7 +202,7 @@ def ell(
         if extension < 0:
             ext_floor = -numpy.floor(extension)
             raise BuildError(f'Position is too close by at least {ext_floor}. Total extensions would be\n\t'
-                             + '\n\t'.join(f'{key}: {off}' for key, off in zip(ports.keys(), offsets)))
+                             + '\n\t'.join(f'{key}: {off}' for key, off in zip(ports.keys(), offsets, strict=True)))
 
-    result = dict(zip(ports.keys(), offsets))
+    result = dict(zip(ports.keys(), offsets, strict=True))
     return result
diff --git a/masque/ports.py b/masque/ports.py
index 86eadc4..8f6a817 100644
--- a/masque/ports.py
+++ b/masque/ports.py
@@ -294,14 +294,14 @@ class PortList(metaclass=ABCMeta):
         Raises:
             `PortError` if the ports are not properly aligned.
         """
-        a_names, b_names = list(zip(*connections.items()))
+        a_names, b_names = list(zip(*connections.items(), strict=True))
         a_ports = [self.ports[pp] for pp in a_names]
         b_ports = [self.ports[pp] for pp in b_names]
 
         a_types = [pp.ptype for pp in a_ports]
         b_types = [pp.ptype for pp in b_ports]
-        type_conflicts = numpy.array([at != bt and at != 'unk' and bt != 'unk'
-                                      for at, bt in zip(a_types, b_types)])
+        type_conflicts = numpy.array([at != bt and 'unk' not in (at, bt)
+                                      for at, bt in zip(a_types, b_types, strict=True)])
 
         if type_conflicts.any():
             msg = 'Ports have conflicting types:\n'
@@ -502,8 +502,8 @@ class PortList(metaclass=ABCMeta):
             o_offsets[:, 1] *= -1
             o_rotations *= -1
 
-        type_conflicts = numpy.array([st != ot and st != 'unk' and ot != 'unk'
-                                      for st, ot in zip(s_types, o_types)])
+        type_conflicts = numpy.array([st != ot and 'unk' not in (st, ot)
+                                      for st, ot in zip(s_types, o_types, strict=True)])
         if type_conflicts.any():
             msg = 'Ports have conflicting types:\n'
             for nn, (k, v) in enumerate(map_in.items()):
diff --git a/masque/shapes/arc.py b/masque/shapes/arc.py
index aa171ed..da10d0d 100644
--- a/masque/shapes/arc.py
+++ b/masque/shapes/arc.py
@@ -324,7 +324,7 @@ class Arc(Shape):
 
         mins = []
         maxs = []
-        for a, sgn in zip(a_ranges, (-1, +1)):
+        for a, sgn in zip(a_ranges, (-1, +1), strict=True):
             wh = sgn * self.width / 2
             rx = self.radius_x + wh
             ry = self.radius_y + wh
@@ -435,7 +435,7 @@ class Arc(Shape):
 
         mins = []
         maxs = []
-        for a, sgn in zip(a_ranges, (-1, +1)):
+        for a, sgn in zip(a_ranges, (-1, +1), strict=True):
             wh = sgn * self.width / 2
             rx = self.radius_x + wh
             ry = self.radius_y + wh
diff --git a/masque/shapes/shape.py b/masque/shapes/shape.py
index 9f5dd19..b7b74d6 100644
--- a/masque/shapes/shape.py
+++ b/masque/shapes/shape.py
@@ -135,7 +135,7 @@ class Shape(PositionableImpl, Rotatable, Mirrorable, Copyable, Scalable,
 
             vertex_lists = []
             p_verts = polygon.vertices + polygon.offset
-            for v, v_next in zip(p_verts, numpy.roll(p_verts, -1, axis=0)):
+            for v, v_next in zip(p_verts, numpy.roll(p_verts, -1, axis=0), strict=True):
                 dv = v_next - v
 
                 # Find x-index bounds for the line      # TODO: fix this and err_xmin/xmax for grids smaller than the line / shape
diff --git a/masque/utils/comparisons.py b/masque/utils/comparisons.py
index 5de8f4a..63981c9 100644
--- a/masque/utils/comparisons.py
+++ b/masque/utils/comparisons.py
@@ -29,7 +29,7 @@ def annotations_lt(aa: annotations_t, bb: annotations_t) -> bool:
         if len(va) != len(vb):
             return len(va) < len(vb)
 
-        for aaa, bbb in zip(va, vb):
+        for aaa, bbb in zip(va, vb, strict=True):
             if aaa != bbb:
                 return annotation2key(aaa) < annotation2key(bbb)
     return False
@@ -55,7 +55,7 @@ def annotations_eq(aa: annotations_t, bb: annotations_t) -> bool:
         if len(va) != len(vb):
             return False
 
-        for aaa, bbb in zip(va, vb):
+        for aaa, bbb in zip(va, vb, strict=True):
             if aaa != bbb:
                 return False
 
diff --git a/masque/utils/pack2d.py b/masque/utils/pack2d.py
index 7405406..5de9728 100644
--- a/masque/utils/pack2d.py
+++ b/masque/utils/pack2d.py
@@ -236,7 +236,7 @@ def pack_patterns(
     locations, reject_inds = packer(sizes, containers, presort=presort, allow_rejects=allow_rejects)
 
     pat = Pattern()
-    for pp, oo, loc in zip(patterns, offsets, locations):
+    for pp, oo, loc in zip(patterns, offsets, locations, strict=True):
         pat.ref(pp, offset=oo + loc)
 
     rejects = [patterns[ii] for ii in reject_inds]