The drawings and paintings included lots of hand stencils made by putting a hand up against a rock and blowing liquid ochre onto it — as well as paintings of animals and of stick-figure humans ...

At some point in those long millennia of habitation, some of them left behind hand stencils ... of the ability to use symbols, like stick-figure animals on a cave wall or spoken language.

It starts with stick figures and goes all the way through muscles ... with vellum paper layers, a speech-bubble stencil and fold-out progressions. By the end of the weekend, my son had made ...