The 2,300-Year-Old Wheel Puzzle That Almost Broke Math

Grab two coins of different sizes — say, a big euro coin and a small coin

If you roll the large coin across your desk for exactly one full turn, it covers a good amount of distance.

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If you roll the small coin for one turn, it covers much less.

That makes complete sense: a bigger circle has a bigger perimeter (circumference), so one rotation takes it farther.

Now, imagine gluing the small coin directly to the center of the big coin, like a bullseye.

Set the whole thing on a table and roll the big coin forward for one full spin.

Here is the weird part: both coins just traveled from point A to point B together. They…