I have one somewhere and you are a crafty sod. It’s a carpenters ruler. You straighten it at the hinge…then the other arms fold out from underneath on hinges. You have photographed it so you can’t see those other arms
Good guess, I know what you mean but you are wrong🤣 .
Look carefully at the markings.
Elcarajillo Proportional sector?
Yes that is what it is 👍
I’m on fire today. :-)
Gagaryn I’m on fire today. :-)
and drinking my tears of failure!
