I just found the cutest site. They have an art project using melted crayons for finger painting. The site is Dilly-Dalli Art.
The theme of the site is:
I am teaming up with Childhood Beckons to bring you a biweekly series incorporating items from nature into art and play settings!
Every other week we will choose one item found in nature Childhood Beckons will have a play idea with the item
and I will have an art/craft idea with the same item!
Art and music are tied to math skills and help develop the foundations for Math and Science in the future. I remember melting crayons onto a light bulb when I was a kid and then using the wax to paint. This blog includes a method that seems a lot safer!
Check out this article on Wikipedia about the tie between Math and Art. This activity looks like it would also be fun for kids with sensory issues. Depending on how melted the way the texture will be different and the final painting will make a rough surface that is pretty cool! I would bet you could even add items into the painting (glue with the wax) before it dries. Maybe add some beads, buttons, or other small objects.