There are three light switches outside the room and three
lamps inside the room. If you can only enter this room once,
how would you determine which switch controls which lamp?
Congratulations to these solvers as of
Marc Cassimon, Eudo Cruz, Steve Dowd, Egon Feller, Albert Frank, David Gill,
Juan Luis Gonzalez, Tolga Goze, Joshua Green, Dave Hagy, Frank Kim, Hanna Krueger,
Napawong Leelaprechalert, Dick Logan, LW Luk, Graham McDonald, Glenn McCorkle,
T.J. Martin, Charlie Meyers, Uwe Nebel, Hans Poschmann, Lauren Riley,
Matthew Robinson, Bernard Sojka, Jack Stacey, Steve Steppe, Luc Vingerhoets,
Marc Wakem and Dave Washburn.