Color a design on rough sandpaper with neon, metallic and/or construction paper crayons. (this will transfer in a mirror image, so be careful with lettering).
Flip the sandpaper over and circulate a warm iron on medium setting over the back onto either white or black paper. The crayon will transfer to the paper.
**Heating crayons with an iron should be done in a well-ventilated area. Overheating wax crayons may release irritating fumes. Ironing should be done by an adult.