Video demonstration:http://www.youtube.com/watch?v=UlYJBXUPk78It was designed in Google SketchUp (source format included!), exported to watertight STL with the CADspan plugin. Nowadays you can actually directly export a Collada/DAE file from SketchUp and load that into Cura (which accepts that file format).The print quality isn't great for this one, but this was back in 2009 :)