That “prisoners” brain teaser of my prior post actually works for any arbitrary number of colors. For example, the hats could be chosen at random from red, green and blue, or ROYGBV. (I refuse to put Indigo in there because it’s almost the same thing as Blue. It’s basically just dark blue, and they have it there just to make the mnemonic more pronounceable. I learned the spectrum as “red, orange, yellow, green, blue, purple” and I don’t need some silly mnemonic with silly colors like “indigo” and “violet”. It’s just purple, everyone!)

(There should be something that tells you when you’re typing and you forget to close a parenthetical remark. That should be a simple enough feature for a spellchecker, you know, but I don’t think they check that.