MONTIGNAC, France -- Pixar, eat your heart out. Cro-Magnon artists 20,000 years ago painted a picture of a snorting horse whose head seems to move upwards on the wall of the Lascaux cave in southwest France. That, at least, is the illusion visitors have when they see the meticulous reproductions of the famous Lascaux cave…Read more En Route: Lascaux 4 — a high-tech trip back in time