This has been cross-posted to my micro-blog, Tumbld Thoughts.
 For those who are unfamiliar with his work, he's postage stamp worthy (see above image). This used to be a big deal. Perhaps in Europe it still is.
 Mathematical and physical tools such as Euler angles and Euler's disks (here is video demo of Euler angles in the context of a phenomenon called gimbal lock and Euler disks in the context of holographs).