Use spring form cake pan, a dollar store round aluminum foil cake pan, or round plastic garbage can lids to make the circular. Use recycled pizza boxes for square designs and dollar store rectangle aluminum cake pans.
Favorite Part of this is to make a stepping stone path. HOW: cup salt, cup flour, cup (give or take) water. Knead until dough forms. Make impression. Bake at 200 for 3 hours. Do every summer and make a stepping stone path :) What a cute idea!