+
+
+-- | Takes a 'Grid', and returns all 'Cube's belonging to it that
+-- contain the given 'Point'.
+find_containing_cubes :: Grid -> Point -> [Cube]
+find_containing_cubes g p =
+ filter contains_our_point all_cubes
+ where
+ all_cubes = flatten $ cubes g
+ contains_our_point = flip contains_point p