The Penta Poly Test Shape

Originally a lamp-shade, I use this test piece for ringing, speed and flow testing along with other minor calibrations of my printers. It's also handy for figuring out which side of a print dual/tri colour filament is going to work best on.

The shape is two pentagons laid over each other, so the external corners are 108 degrees and the internal corners are 216 degrees, every second face is 36 degrees around (use these numbers for multicolour filament, or to figure out how out of square your machine is, with some trigonometry).

It also makes a great pen cup, and with scaling can make a great key bowl, toothbrush holder, RC/Robot wheel, mould for concrete/plaster stools etc, garden/window pot (for plants) etc

It's just a simple, easy to print shape.

Use vase mode for most functions, or use modifiers to make room for axles etc

Scaling allows for a large selection of shapes.