Window hinge that rotates and translates

A part of my kinetic art project. This is a hinge I designed for a window using maths and plenty of patience. It rotates the window around the outside corner, which remains unattached to anything.

I have mounted one each at the top and bottom of the window and connected them with a special piece so that they move together.

Video here:
https://plus.google.com/u/0/photos/105767091234703883277/albums/5993906468959562673/6067206541258471522?authkey=CLGb9aPa-8_cZQ&pid=6067206541258471522&oi