diff --git a/blender/samples/cube-gimp.json b/blender/samples/cube-gimp.json
new file mode 100644
index 0000000..06a928d
--- /dev/null
+++ b/blender/samples/cube-gimp.json
@@ -0,0 +1 @@
+{"edges": [[4, 5], [5, 1], [1, 0], [0, 4], [5, 6], [6, 2], [2, 1], [6, 7], [7, 3], [3, 2], [7, 4], [0, 3]], "vertices": [[-1.0, -1.0, -1.0], [-1.0, 1.0, -1.0], [1.0, 1.0, -1.0], [1.0, -1.0, -1.0], [-1.0, -1.0, 1.0], [-1.0, 1.0, 1.0], [1.0, 1.0, 1.0], [1.0, -1.0, 1.0]], "faces": [[4, 5, 1, 0], [5, 6, 2, 1], [6, 7, 3, 2], [7, 4, 0, 3], [0, 1, 2, 3], [7, 6, 5, 4]]}
\ No newline at end of file
diff --git a/surf/geometry.py b/surf/geometry.py
index c780317..88ab767 100644
--- a/surf/geometry.py
+++ b/surf/geometry.py
@@ -175,25 +175,30 @@ class PolygonMesh(object):
     @property
     def edges_for_face(self):
         """returns a list of edge indices for a given face index."""
+        # XXX
         if self._edges_for_face is None:
-            # TODO: eventually support generating this ourselves ...
-            raise NotImplementedError
+            self._edges_for_face = [[] for i in range(len(self.faces))]
+
         return self._edges_for_face
 
     @property
     def edges_for_vert(self):
         """returns a list of edge indices for a given vertex index."""
         if self._edges_for_vert is None:
-            # TODO: eventually support generating this ourselves ...
-            raise NotImplementedError
+            self._edges_for_vert = [[] for i in range(len(self.vertices))]
+            for i, edge in enumerate(self.edges):
+                for vid in edge:
+                    self._edges_for_vert[vid].append(i)
         return self._edges_for_vert
 
     @property
     def faces_for_vert(self):
         """returns a list of face indices for a given vert index."""
         if self._faces_for_vert is None:
-            # TODO: eventually support generating this ourselves ...
-            raise NotImplementedError
+            self._faces_for_vert = [[] for i in range(len(self.vertices))]
+            for i, face in enumerate(self.faces):
+                for vid in face:
+                    self._faces_for_vert[vid].append(i)
         return self._faces_for_vert
 
     def __unicode__(self):