diff --git a/masque/test/test_boolean.py b/masque/test/test_boolean.py
index e2fd7ea..b8d0538 100644
--- a/masque/test/test_boolean.py
+++ b/masque/test/test_boolean.py
@@ -15,6 +15,40 @@ def _poly_area(poly: Polygon) -> float:
     y = verts[:, 1]
     return 0.5 * abs(numpy.dot(x, numpy.roll(y, -1)) - numpy.dot(y, numpy.roll(x, -1)))
 
+
+@pytest.mark.parametrize('repeated_clip', [False, True])
+@pytest.mark.parametrize('nested', [False, True])
+def test_boolean_expands_repetitions(repeated_clip: bool, nested: bool) -> None:
+    from masque import boolean
+    from masque.repetition import Arbitrary
+    from masque.shapes import RectCollection
+
+    repeated = RectCollection([[0, 0, 2, 2]], repetition=Arbitrary([[0, 0], [10, 0]]))
+    clip = Polygon([[10, 0], [12, 0], [12, 2], [10, 2]])
+    subject, other = (clip, repeated) if repeated_clip else (repeated, clip)
+    result = boolean([[subject]] if nested else subject, [other], operation='intersection')
+    assert len(result) == 1
+    assert_allclose(result[0].get_bounds_single(), [[10, 0], [12, 2]])
+    assert _poly_area(result[0]) == 4
+    assert result[0].repetition is None
+    assert_allclose(repeated.rects, [[0, 0, 2, 2]])
+    assert_allclose(repeated.repetition.displacements, [[0, 0], [10, 0]])
+
+
+@pytest.mark.parametrize('operation', ['union', 'difference', 'xor'])
+def test_boolean_single_set_normalizes_overlaps(operation: str) -> None:
+    from masque import boolean
+
+    subject = Polygon([[0, 0], [2, 0], [2, 2], [0, 2]], repetition=Grid(a_vector=(1, 0), a_count=2))
+    for clips in (None, []):
+        result = boolean(subject, clips, operation=operation)
+        assert len(result) == 1
+        assert _poly_area(result[0]) == 6
+    if operation != 'difference':
+        result = boolean([], subject, operation=operation)
+        assert len(result) == 1
+        assert _poly_area(result[0]) == 6
+
 def test_layer_as_polygons_basic() -> None:
     pat = Pattern()
     pat.polygon((1, 0), [[0, 0], [1, 0], [1, 1], [0, 1]])
diff --git a/masque/utils/boolean.py b/masque/utils/boolean.py
index 5181fc5..9dd43bd 100644
--- a/masque/utils/boolean.py
+++ b/masque/utils/boolean.py
@@ -89,8 +89,8 @@ def boolean(
     Perform a boolean operation on two sets of polygons.
 
     Args:
-        subjects: List of subjects (Polygons or vertex arrays).
-        clips: List of clips (Polygons or vertex arrays).
+        subjects: Subjects (shapes or vertex arrays). Shape repetitions are expanded.
+        clips: Clips (shapes or vertex arrays). Shape repetitions are expanded.
         operation: The boolean operation to perform.
         scale: Scaling factor for integer conversion (pyclipper uses integers).
 
@@ -115,44 +115,31 @@ def boolean(
     def to_vertices(objs: Iterable[Any] | Any | None) -> list[NDArray]:
         if objs is None:
             return []
-        if hasattr(objs, 'to_polygons') or isinstance(objs, numpy.ndarray | Polygon):
-            objs = (objs,)
-        elif not isinstance(objs, Iterable):
+        if isinstance(objs, numpy.ndarray):
+            return [objs]
+        if hasattr(objs, 'to_polygons'):
+            verts = []
+            for poly in objs.to_polygons():
+                if poly.repetition is None:
+                    verts.append(poly.vertices)
+                else:
+                    verts.extend(poly.vertices + dd for dd in poly.repetition.displacements)
+            return verts
+        if isinstance(objs, str | bytes) or not isinstance(objs, Iterable):
             raise PatternError(f"Unsupported type for boolean operation: {type(objs)}")
-        verts = []
-        for obj in objs:
-            if hasattr(obj, 'to_polygons'):
-                for p in obj.to_polygons():
-                    verts.append(p.vertices)
-            elif isinstance(obj, numpy.ndarray):
-                verts.append(obj)
-            elif isinstance(obj, Polygon):
-                verts.append(obj.vertices)
-            else:
-                # Try to iterate if it's an iterable of shapes
-                try:
-                    for sub in obj:
-                        if hasattr(sub, 'to_polygons'):
-                            for p in sub.to_polygons():
-                                verts.append(p.vertices)
-                        elif isinstance(sub, Polygon):
-                            verts.append(sub.vertices)
-                except TypeError:
-                    raise PatternError(f"Unsupported type for boolean operation: {type(obj)}") from None
-        return verts
+        return [vertices for obj in objs for vertices in to_vertices(obj)]
 
+    op = op_map[operation.lower()]
     subject_verts = to_vertices(subjects)
     clip_verts = to_vertices(clips)
 
     if not subject_verts:
-        if operation in ('union', 'xor'):
-            return [Polygon(vertices) for vertices in clip_verts]
-        return []
-
-    if not clip_verts:
-        if operation == 'intersection':
+        if op not in (pyclipper.CT_UNION, pyclipper.CT_XOR) or not clip_verts:
             return []
-        return [Polygon(vertices) for vertices in subject_verts]
+        subject_verts, clip_verts = clip_verts, []
+
+    if not clip_verts and op == pyclipper.CT_INTERSECTION:
+        return []
 
     pc = pyclipper.Pyclipper()
     pc.AddPaths(pyclipper.scale_to_clipper(subject_verts, scale), pyclipper.PT_SUBJECT, True)
@@ -160,7 +147,13 @@ def boolean(
         pc.AddPaths(pyclipper.scale_to_clipper(clip_verts, scale), pyclipper.PT_CLIP, True)
 
     # Use GetPolyTree to distinguish between outers and holes
-    polytree = pc.Execute2(op_map[operation.lower()], pyclipper.PFT_NONZERO, pyclipper.PFT_NONZERO)
+    polytree = pc.Execute2(op, pyclipper.PFT_NONZERO, pyclipper.PFT_NONZERO)
+    return _polytree_to_polygons(polytree, scale)
+
+
+def _polytree_to_polygons(polytree: Any, scale: float) -> list[Polygon]:
+    """Convert a Clipper result, bridging holes for masque's polygon representation."""
+    import pyclipper        # noqa: PLC0415
 
     result_polygons = []