Here is the complete kit for you to build your own 'useless machine' that utilizes different mechanical principles. An educational model that can help visualize how different mechanical principles work.It
A Lego Technic steam machine powered by two pneumatic cylinders engine, with valve gear mechanism, speed indicator, air control valve and building instructions. The pneumatic cylinders and the switches are
Variable Speed Geneva Disk, a LEGO GBC (Great Ball Contraption) by Takanori HashimotoTakanori Hashimoto GBC modules are always relying on remarkeable mechanisms. And his last creation, "Variable Speed Geneva Drive"