Horvath G, Farkas E, Boncz I, Blaho M, Kriska G (2012) Cavemen Were Better at Depicting Quadruped Walking than Modern Artists: Erroneous Walking Illustrations in the Fine Arts from Prehistory to Today. PLoS ONE 7(12): e49786. doi:10.1371/journa
December 5, 2012 5:10 PM
A sketch by Leonardo da Vinci (A) shows improper foot placement (B). Images C and D show how the image could be corrected to show the horse walking correctly.