In mathematics, the **mice problem** is a problem in which a number of mice (or bugs, dogs, missiles, etc.), starting from the corners of a regular polygon, follow each other and it must be determined when they meet.

The most common version has the mice starting at the corners of a unit square, moving at unit speed. In this case they meet after a time of one unit, because the distance between two neighboring mice always decreases at a speed of one unit. More generally, for a regular polygon of *n* sides, the distance between neighboring mice decreases at a speed of 1 − cos(2π/*n*), so they meet after a time of 1/(1 − cos(2π/*n*)).^{}^{
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For all regular polygons, the mice trace out a logarithmic spiral, which meets in the center of the polygon (as shown on the right).