Concept
Integral geometry
2 essays name this object, across 2 fields. What follows is each of them, and the objects they name alongside it.
Getting pi by dropping needles on the floor
Throw a needle at a lined floor enough times, count how often it crosses a line, and pi falls out. There is no circle anywhere in the experiment.
Round is not the only way to be the same width
A shape that measures the same in every direction sounds like a description of a circle. It is not — there are infinitely many others, one of them is on a coin in most people's pockets, and a drill built from one cuts a nearly square hole.
Named alongside it
The objects these essays reach for when they reach for this one.
PiAreaBarbier's theoremBuffon's needleConstant widthConvergenceConvergence rateConvexityEstimator biasIndependenceMonte CarloReuleaux triangle