ref: 712abb7719440e132750fedf1bab60db9c1023fd
parent: 43bea5f6f20b4a58b083ccb0b380e78180017128
author: Ben Harris <bjh21@bjh21.me.uk>
date: Mon Dec 12 16:09:32 EST 2022
Add an assertion that all colours are within range Because I know I'm going to mess this up at some point.