this ruler at first glance looks perfectly normal. (if you ignore the color scheme) but its actually slightly off. with every inch being to short. so unless you have a very good idea of how long a foot is, which most people don't, you won't be able to tell. just don't give it to a carpenter.

you will have to print it diagonal to fit on a 256 mm build plate. and to make it to color pause the print at layer 33.