A downloadable game for Windows, macOS, and Linux
Some of the first programs I wrote on an Apple II back in the day were methods of computing pi that I found in a library book on the history of pi. Here's one of those methods, implemented as a Processing app: calculates pi by randomly generating points (think of it as throwing darts at a board) within a square bounding a circle. The ratio of points inside the circle to the total points (approximating the area of the circle divided by the area of the enclosing square) should converge to pi/4.
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