Prepare Color Flow icing. Tint portions gray and black. Using tip 3 and full-strength gray icing, outline tombstone cookies. Using tip 3 and thinned gray icing, fill in. Let dry overnight.
Use tip 7 and full-strength gray icing to outline cookie. Use tip 2 and full-strength black icing to pipe inscription on tombstone cookies. Let dry.
Melt white Candy Melts candy according to package directions. Attach easels to back of tombstone cookies with melted white candy.