Made in the fablab of the RWTH Aachen (http://hci.rwth-aachen.de/fablab) and for testing a program made in a project course (http://hci.rwth-aachen.de/cutcad - the program itself is not fully functional yet, but at least for this thing it works).
Made out of 2mm wood (birch plywood is more stable, but looks not as well as lime wood). Lasercutted, stained and glued together.
So you need a DinA4 sheet of 2mm material and a lasercutter (or a fretsaw and much time :-), staining agent (optional, here i used Aqua Clue 2522 - cherry) and of course glue.
If you want to build it yourself, a pdf file of the shapes is attached.
Next step: Let the laser cutter do all the work...
If you like, apply stain agent with a cotton sheet on both sides of each piece before assembling for a better look.
Then glue all pieces together.
There are four different kinds: One with all corners intruded (bottom), one with all corners extrudered (top, do not glue that tenons to have this piece removable to insert the light) and two rings of 5 pieces (one corner extruded bottom ring, two corners extruded top ring).
The exakt location can be viewed in the cutCAD 3D view or in the screenshot one step before (Hint: it is kind of symmetric, and the left side on the grid is the bottom :-)