I really meant to go to bed early after a tiring week's work, but #adventofcode2020 kept me up until midnight and I'm still not done with day 4 part 2. Curse you @dsilverstone!

oh dear. It is a fiddly set of checks. Ping me if you want as non spoilery a hint as I can manage

I may forgive you eventually. What made it worse was waking up at 4am with my brain was firing on all cylinders, randomly throwing up wild but plausible solutions to work problems. I had to write them all down to exorcise them and go back to sleep!