The sphericon is a solid that has a continuous developable surface with two congruent semi circular edges, and four vertices that define a square.  In short, sphericons are awesome!  They are fun to play with and make a great desktop curio. The image shows the sphericon after being 3-D printed on a Form 2 (left).  The 3-D printed sphericon was used to create a mold into which we poured molten aluminum.  The sphericon on the right is the aluminum one.  These were created in our school makerspace. All proceeds from the sale of this design go toward maintaining the school makerspace.