I do a lot of product design and found that it's difficult to get a good idea in your head of how thick or thin a wall will be just off of a number, so I made this tool to use as a visual reference. It sits on my desk and has been used many times when trying to determine whether a certain thickness of wall will be strong enough just based on appearances.

It has both walls and gaps, starting at 1/32, and increasing by 1/32 each time. (Sorry, it's imperial, but if somebody makes a metric version it'd be a cool remix). The spaces between the walls and spaces between the gaps are the same measurements in reverse order.

The text on the tool may or may not print well, but isn't critical. I just penciled on the measurements for the walls.

Infill design isn't important, so long as you use whatever gets you the closest to true dimensions.