spoiler
For people that don’t know this is not how you use Calipers
This just tells me calipers should have 2 measuring bars on them, so gaps and other inside edges can be measured like this (maybe this already exists, idak)
Can’t tell if I’m missing a joke here, but see those two small knife looking protruding from the opposite side (above) where they’re measuring, those are used for measuring internal diameter.
The side they’re using is for outer diameter.
And though you can’t see it in the pic, the thin bit of metal that extends out from the bottom can be used for measuring depth.
That’s what the two prongs at the top are for. Flip the caliper upside down, use the prongs to measure the inside dimension, and read it off the same scale.
“Caliper jaws for inside measurement—I thought of that. Turned out it already existed, but I arrived at it independently."