Customized version of http://www.thingiverse.com/thing:53916

Created with Customizer! http://www.thingiverse.com/apps/customizer/run?thing_id=53916

Using the following options:

wallWidth = 2
baseThickness = 0
Radius_of_rotating_ring = 10
Segments = 300
Radius_of_fixed_ring = 20
twistCycles = 0.4
layerHeight = 10
isHypotrochoid = 0
turns = 6
Distance = 10
height = 120