You can watch a videostream of Cholla painting at his easel :
http://www.artistisahorse.com
Cholla is a Mustang/Quarter Horse born in 1986 and started painting in 2004. He uses a real artist brush and paints with water colors at his easel. No one moves the paper or easel. Only Cholla applies the paint to his creations. He is a true artist. The evolution of the horse?