The instructions, by the way, are at http://phdchallenge.com, which got cut off.

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I wonder why elevator buttons aren’t toggle buttons… Many a time the wrong button is pressed and the elevator must then take the extra time to stop, when cancelling the mistake would have been quick and efficient.

This has got me thinking about elevator algorithms (i.e. real elevator algorithms, not the elevator algorithm).

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Saw some advice on what to do in case your elevator loses power and starts to freefall. Things like pushing all the buttons, standing against the wall, etc. I’d like to ask an even more basic question: Why would this scenario even happen? Has it ever happened? If so, it must have been an elevator with incredibly bad engineering.

I don’t know how elevators actually are designed, but I know they have counterweights and brakes. So if I were to design them, I’d be sure the brakes are always engaged mechanically by default, and only could be released under power. I would then make sure the shaft is long and there is an emergency spring-loaded bungee cord to make sure the elevator never hits bottom. I’d even add enough padding at the bottom and make sure the shaft below first floor (where the elevator is not supposed to go) are entirely made of braking material. How could anybody die by falling in such a design?

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