Here are three cat bowls designed for dual extrusion. They are derivatives of thing:50076 Decorated Water Bowls. The decorations are variations on a cat image by MaakMijnldee - thing:35495. They illustrate the symmetry of 3 of the wallpaper groups, p3, p4, and pmm.
The bowls are 110 mm in diameter and 28 mm hight and hold over 7 ounces of food or water. Three pairs of stl files are provided:
pmm_cat_bowl.stl and pmm_cat_decoration.stl
p3_cat_bowl.stl and p3_cat_decoration.stl
p4_cat bowl.stl and p4_cat_decoration.stl
The images are in dxf_files.zip and the program that created the stl files is bowl_cat.scad.