Here's an animation of a hinged dissection: http://sylvester.math.nthu.edu.tw/d3/thesis-2003/yang/dissection/hinged.htm http://sylvester.math.nthu.edu.tw/d3/the

Here's an animation of a hinged dissection: http://sylvester.math.nthu.edu.tw/d3/thesis-2003/yang/dissection/hinged.htm http://sylvester.math.nthu.edu.tw/d3/thesis-2003/yang/dissec... It was linked to at the bottom of the Wikipedia page.