[mywholebodyisaweapon]

It was commonly known as “The Four Color Problem,” with four conjectured as the minimum number of colors mapmakers could use to represent countries so that no two adjacent countries would have the same color.

Guess now it will be known as “The Five Color Problem.”

[KarlInOhio]

The four color map problem has been proven where only four colors are needed to color a map so that no two touching regions are the same color. This is a more general problem in which no two points a given distance apart are the same color.

https://en.m.wikipedia.org/wiki/Hadwiger–Nelson_problem

Also "The Hadwiger-Nelson problem" sounds like an episode title for The Big Bang Theory where Sheldon does something clueless and upsets everyone.