He included a live demo. It made a very satisfying "kachunk-kachunk-kachunk" sound as it multiplied two numbers. It also made me realize that the threshold of complexity necessary to construct a practical turing-complee computing device is quite low.
(Unfortunately the small demo isn't doesn't run to completion, perhaps because the source material didn't include it, or because uploading it all would have been nontrivial)
http://www.nablaman.com/relay/