Because it's Friday: How Machines Work

Ever wondered how a sewing machine seemingly manages to knot stitches without ever releasing the thread? Well, wonder no more:

 

Find this and other animations of marvels of engineering, including the universal velocity joint and the rotary engine, at the link below.

World Of Technology: Complicated Mechanisms Explained in simple animations (via)
 

http://mytechnologyworld9.blogspot.com/2010/08/complicated-mechanisms-explained-in.html