[protomyth]

Other than some of the stuff on the Wikipedia article and the double inverted pendulum, I used it with a weird heating problem and some social stuff.

So, there is this material that needs to be heated on a curve (time 0 = room temp, 20 minutes = 400C, 120 minutes = room temp - cannot remember after 20 years - it cooled sorta quickly because of fans when heater off). Software package with oven basically turned heaters full blast, the off, then full blast, etc. about half the time material wasn’t cooked properly. I wrote a bunch of rules that computed a % the heater should be at. Worked really well and was an amazingly small program.

Social wise I wrote rules to judge success based on about 20 factors. Never bothered to pursue it beyond my own satisfaction.