Mathematics
Quadratic Reciprocity and Its Proofs
Quick fact
Quadratic reciprocity was first proven by Carl Friedrich Gauss in 1796, and he later published six distinct proofs, calling it the 'golden theorem' of number theory.
Why this is interesting
You know that some numbers are perfect squares, but what about 'squares below a clock'? The question of whether one prime is a square modulo another has a hidden symmetry—one that even Gauss found captivating.