No need to build three, you just have to quickly write a proof for which shapes can roll. You'll then spend x+y units of time, where y<<x, instead of 3*x units.

No need to build three, you just have to quickly write a proof for which shapes can roll. You'll then spend x+y units of time, where y<<x, instead of 3*x units. We have stories that highlight the importance of thinking instead of blindly doing (sharpening the axe, $1 for pressing a button and $9999 for knowing which button to press).