n-Sphere Tiles
Designed as an educational toy for my son, the n-Sphere toy is a little puzzle box with no wrong answers. The sphere can be assembled any combination of 6 tiles oriented in any rotation and will always yield a continuous topology of ridges and grooves along the outer surface.
This version is designed with a flat base surface so no support needed with the makerbot.

Version 2 updated for Medium Resolution prints at:
http://www.thingiverse.com/thing:88003

Full spherical shell version available at:
Original (baseball size): [apx. $69]
http://www.shapeways.com/shops/na?section=n-Sphere+Full&s=0

Mini (racquetball size): [apx. $39]
http://www.shapeways.com/shops/na?section=n-Sphere+Mini&s=0

Micro (golf ball size): ]apx. $21]
http://www.shapeways.com/shops/na?section=n-Sphere+Micro&s=0