A partially colored in "McGregor" map

If you’ve studied math (or geometry in particular), you might know that it’s possible to color any map so that no two areas that are touching have the same color, using only four colors.

A book I was reading about the four-color theorem mentioned in passing a 70’s era April Fools joke by Martin Gardner, purporting to have disproven the four-color theorem with a giant “map” of more than 100 regions. The joke is that it is actually solvable with four colors! (Mathematicians have an even wilder sense of humor than programmers.) There are dozens if not hundreds of reproductions of the “McGregor map” (named after the fictitious graph theorist who supposedly developed it) online, but to my surprise, none of them are interactive…until now. You’re welcome, math nerds.

Can you solve the “Mcgregor map”?

(It’s also kind of fun to look at. If I ever solve it, I think I’ll make a quilt out of the result.)