Here's a flat, piped version of the Day of the Dead sugar skulls. Those are usually way too intricate and pretty to actually consider eating; these can be made in a few minutes with stiff consistency royal icing and food-safe markers. You'll also need round tip #12, parchment paper squares, a flower nail, a glue stick, a Styrofoam block to rest the nail in, and a dusting pouch filled with a 50/50 blend of powdered sugar and cornstarch. Start by sticking a parchment square to the flower nail with a dab from the glue stick.
Lastly, decorate them any way you like; the more colors the better. I like Gourmet Writers by AmeriColor (make sure the icing is completely dry before you start and not merely crusted over; the pen tips may pierce the surface, which is not the look you're going for).