The page contains many great photographs of the piece as a work-in-progress. They also describe in some detail the method of constructing the brass crank shaft. You have got to respect the fact that such a beautifully crafted part isn't even a visible part of the piece!
An excerpt from their page:
What initially started as an experimental prototype design became this one-of-a-kind Monkey Automaton, the first of a series. The internal crankshaft design enables the brass hand-crank mechanism to operate at varied speed, in forward or reverse. The Monkey figure moves in a rhythmic side-to-side motion with alternating leg kicks. The loose jointed arms are secured to the legs which creates the illusion of more movement without having to add to the mechanism.
Visit the Chomick+Meder prototype automaton page to learn more.