Planimeter - photo

[Toolmaker51]

Or you can just use your pocket knife...

https://spaco.org/Blacksmithing/FinnishPlanimeter.htm

as a form of Prytz planimeter...

https://www.jstor.org/stable/2971268...o_tab_contents

Nope;

While I appreciate the Prytz, this one was a small priyce, cased and elegant. Reminded by idea from PJ's in ways to scale things, especially pictures. Always had a thing for K&E anyway, had this since '77. Just need to know size of something on the same sheet. Another winning scaling instrument is proportional divider
The pocket knife is creative, but looks tedious for curved shapes.