About this 3D model

tried to bang this out as quickly as possible to win 9000 internet points ( http://www.makerbot.com/blog/2011/09/29/openscad-puzzle-challenge-how-would-you-make-this/) openscad's modular nature made this challenge pretty easy. make one shpere with 3 square through-holes, then repeat 3 times with a different radius.