(...) It is indeed a noteworthy invention. Please note, however, that the DAT file linked to from the web page has an error: you need to substitute part 2825.dat (Technic liftarm 1x4 with boss) for the part 32017.dat (Technic liftarm 1x5) that is (...) (16 years ago, 22-Mar-09, to lugnet.technic)
See (URL) the original post. I have just built this device, and I am blown away by the genius and simplicity of its operation. Very well done indeed. Owen. (17 years ago, 9-Feb-08, to lugnet.technic) !