Customizable Hole Size Tester

This customizer lets you spit out a very simple object -- a block with holes in it. But that block has been really useful to me, and I hope it's useful to you too.
* Not sure what size hole you need in your design to fit a real-world object? Print out all the plausible-sized holes at once and find out, rather than using trial and error.
* Not sure how much your printer is altering the design size of holes? Print this out, measure the actual size of the holes versus the design size, and find ou