My 19-month old daughter was quite the finite state machine today.

She's recently become mobile and ended up getting her finger caught in a door for the first time. It gave her a little blood blister and the new experience inspired her to cry for a very very long time. My wife tried everything to get her to stop crying. She eventually put her in her crib. When she took her out of the crib, our daughter stopped crying.

Here's how I see it: Our daughter normally cries when first placed her in crib, and stops crying when taken out. So that action triggers the state transition ("crying because I'm in the crib" --> "not crying"). By placing our daughter in the crib, my wife got her from an unknown state ("crying because I just hurt myself in a new way") to a known state ("crying because I'm in the crib"). Once in a known state, she could follow the known state transitions to get her to a more desirable state ("not crying").

That's not what they teach you in the parenting classes, but since it worked, I can't argue with success!

(This reminds me of what my dog taught me about race conditions.)