A 2.00 inch (50.80mm) test cube I designed in order to test a machines ability to print overhangs, small features, thin walls, part accuracy and overall speed. This also helped us test software for creation of easily removable supports. One area in particular that most machines tested struggled with was the bottom of the suspended ball, which would often look very distorted.

My design was sent to GCreate when evaluating their printers, which they have another version of my part which you may like better: https://www.thingiverse.com/thing:1437289

Parts can be assembled to one another, making some interesting desktop artwork.

NOTE The image of the STL file is shown upside down. The part bottom has the text "BOTTOM" on it. This is the print orientation the part was designed for.