Four Colors on a Quilt Frame
Every quilt I ever made starts the same way —
a pile of scraps and one stubborn question.
— Carolyn Stanfill · Burlington, NC
No two patches that touch
may wear the same color.
Guthrie's Problem · 1852
Four colors are always enough.
Every map. Every quilt. Every country.
Guaranteed.
The Computer Proved It · 1976
For 124 years it stayed unproven.
Then Kenneth Appel and Wolfgang Haken
checked 1,936 cases — by machine.
the first great theorem proven by a computer
It's not magic, darling —
it's math, with the soul of a quilt.