I tried a few times with PLA but something kept coming unstuck from the bed and ruined the print. Recently I switched to trying out ABS and managed to get a decent hollow pyramid without much stringing so I figured I'd give the tank treads another try.
However, I'm impatient so I printed it at half size

It looked good on the bed:
Unfortunately, the tread spacing a we're too right (I could tell while it was printing) and they broke as soon as I tried to loosen them to move. So instead of tank treads I got two planetary gear wheels attached to a bar

Edit: oh, and as another symptom of my impatience, I printed at .3mm layer height, so that probably contributed to the failed belts as well!