Painting a what?

I just finished up a very unusual painting, trading my usual canvas for a rock! Yes, the result of this side-project is shown on the left. There is a story for this too.

My nephew ran on the track team in high school, and the rock is supposed to resemble his favorite pair of running shoes. George Witham, a fellow artist with a rock painting background, taught me the ins and outs of making a realistic painting on one of nature's three-dimensional

I call the above painted rock "The Running Shoe" (yes, this is a picture of a very real, shoe-shaped rock I painted)