I got this from Mr Wizard as a kid and use it infrequently but regularly when making things and needing to split a piece of material in two. I know it's the CG

I got this from Mr Wizard as a kid and use it infrequently but regularly when making things and needing to split a piece of material in two. I know it's the CG and not the geometric center, but is often close enough with reasonably uniform material.