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Creation Date

Fall 2014


White plastic Mobius figure 8 knot with steel ball designed to move within the groove of the knot


Replaced the concave triangle cross section with a circle with three smaller circles removed so that the resulting groove that goes around the knot three times before returning to its starting point. A 1/4" diameter steel ball bearing inserted into the groove would be held in because the diameter of the ball is slightly larger than the opening of the groove. The first version printed by Shapeways did not work well because the groove .005" larger than the diameter of the ball, and the ball would not freely roll around the groove. It was redesigned it with a larger groove (.015" larger than the diameter of the ball), and the result is shown in the following picture. The ball is easily pushed into the groove, since the plastic is flexible, and stays in the groove all around except at one sharp curve, where the opening is too wide.


Rights belong to Alex Feingold