Sphericon
thingiverse
this may look like a square, but it rolls like a cylinder or sphere. Only in a zigzag pattern ;)
Download Model from thingiverse
With this file you will be able to print Sphericon with your 3D printer. Click on the button and save the file on your computer to work, edit or customize your design. You can also find more 3D designs for printers on Sphericon.