Mathematics
Group Theory and Symmetries of Geometric Objects
Quick fact
The symmetries of a regular n-gon form a group of exactly 2n transformations, combining rotations and reflections, known as the dihedral group Dₙ.
Why this is interesting
You've probably noticed that a square can be rotated 90° and still look the same—but have you ever wondered what all the ways to move it that leave it unchanged are?