Universal joint. love this. wish I'd seen it before. just made my elephant.
This universal joint makes my brain feel good.http://imgur.com/gallery/5qWvrTD
Laser-cut universal joints.
Universal Joint - STEP / IGES, SOLIDWORKS - 3D CAD model - GrabCAD
How to Replace the Universal Joint on Your Car or Truck: Finished and Ready for Installation
pin joint - Google Search
(hit the 2x) This is a Cardan Joint (or Universal Joint). Its velocity is not constant -- check out the attachment to see the math describing the variation in speed.
Universal Joint (Graphite Bushes) - STEP / IGES,STL,Autodesk Inventor - 3D CAD model - GrabCAD
Drive shaft removal. - photo by John Lake, 2011