So I found this on the XKCD forums, and I just had to share it with you guys
It's a classic puzzle with a nice, formal proof of solution.
Near the end, there's a solution for sending arbitrary messages to all prisoners, using only 1 light-bulb; it's P2P-ish.
http://www.segerman.org/prisoners.pdfWoW! That's the type of puzzle I used to play with when I was a kid. Sadly, not any more, with the exception of donning a tinfoil hat every now and then when it comes to Bitcoin.
~Bruno~