This is actually easier than it looks. Glue crayons to a piece of cardboard or to the a canvas. Then get a blow dryer, tunr it on, and hold at an angle. The crayon will start to melt and drip in the direction of the hot air. Put cardboard behind the art piece, the crayon will splatter. You can also do this by placing the art outside if it is over 100 degrees.
Christian Faur’s crayon art looks more like a rasturbated photograph than a portrait made of colored crayons. After scanning a photo, Faur breaks the picture down into color blocks. Then he closely aligns thousands of colored crayons to recreate the image. Truly amazing!