Murkelcopter - quad copter frame

This is a frame for a quadrocopter made out of 2mm birch plywood. It is designed for manufacturing using a 3-axis CNC mill or an Laser-Cutter.
The frame was designed in XMAS 2010 and has successfully tested by over 20 builders during the last year.

A full description of the project can be found here:
http://www.flugwiese.de/index.php/projekte/41-schaummodelle/112-murkelcopter
(unfortuneately all in German, but a lot more pictures and links to english pages)

Why is it called the "Murkelcopter" ? Well, the name was given to it by my daughter when she saw the first prototype of the frame