A food vending machine, similar to the one on the right, was recently installed in the lab. It’s been giving us some trouble lately. Mostly the common failure mechanism of not supplying goods despite cash. The trouble is with the sliding door. A special—undocumented, mind you—procedure needs to be followed in order to get goods.
1. position tray to desired item.
2. insert cash.
3. slide door until stuck and release (it does not open all the way; this is to indicate to the machine which item you chose so two or more doors could not be opened simultaneously.)
4. slide door open again.
5. get item.
6. enjoy crappy food specially designed for graduate students with no life who need them to survive at night.
I asked Robert Watson (who was already home) though our irc channel if the machine is “safe.” He replied that it was wholly functioning earlier today. Knowing this, I ventured to get a muffin with confidence. I came back with a muffin but still screwed out of cash. I posed the riddle to Robert:
21:38 < rwatson> saar: so something that results in you getting screwed, yet still getting the muffin.
21:38 < saar> rwatson: yes. and it only involves the machine, not other people ;)
Can you guess what happened? It’s a tough one.
I only had one gigantic 2 GBP coin and I inserted it into the machine. Following the procedure above, I also got my double chocolate muffin. Happily, I was futzing around with the sliding door to examine its spring rigidity and the option of invading another compartment ;) Little did I know that since I had a 1.2 GBP credit, the machine charged me 80p AGAIN! So, I payed for that damn, unhealthy, fatty muffin TWICE!
Clearly a design error (NOT user.) I think I’m going on an 80p rampage a la Payback!