From George Hart's Web site, http://www.georgehart.com/sculpture/echinodermania1.html"I like echinoderms, and these are toroidal sculptures inspired by their forms. They are not models of actual species, but more like some kind of parallel universe evolution of maniacal echinoderms. This family is toroidal in form, with the above example making five twists in its cycle. All are made by selective laser sintering of nylon, on an SLS machine, then I dyed them."Barely makeable on my Thing-O-Matic. Someone please try using an Up or Ultimaker.