What is a block? Well, a block is something I wish my Dynamics of Machinery teacher had used many years ago, while he was trying to explain to us the way different mechanisms were supposed to work.  It would’ve been so much easier to understand with SolidWorks and blocks, but, alas, he had no SolidWorks or blocks, so we had to make do with his dinky drawings on a blackboard and the awkward ways...