Here are cat coasters 9 through 12 of the coasters based on the 17 plane groups. See Cat Coasters 01,02 - things 54736 and 56813.

The four plane groups are: cmm. p4, p4m, and p4g. Three of these groups contain four fold rotation axes. p4 has only rotational symmetry, p4m and p4g contain combinations of reflection and glide lines. The four sets of files for dual extrusion are:

cat_coasters_cmm.stl and cat_decorations_cmm.stl
cat_coasters_p4.stl and cat_decorations_p4.stl
cat_coasters_p4m.stl and cat_decorations_p4m.stl
cat_coasters_p4g.stl and cat_decorations_p4g.stl

Cat_coasters_03 scad created the stl files and the images are in coasters_dxf_03.zip

The coasters are 110 mm in diameter and should be constructed directly on the build surface. I used one shell and ten percent infill and the coasters printed in about two hours.

The coasters can be used as teaching aids. Pdf files that show some of the symmetry elements are included in coasters_dxf_03.zip. Reflection lines are shown in red and glide lines in blue.