- Someone pushes a thingy on a table. It
travels 2 metres and falls off the edge,
taking two seconds to do so. Does it have
- Cards face down, Alice can swap two, the
Evil Dictator names one, Bob must find it?
- Alice puts arbitrary integers in boxes
labelled 1, 2, 3, ... Bob can open all
but finitely many, then needs to name the
number in one of the unopened boxes. Can
he do it with non-zero probability?
- 100 prisoners with names in boxes