The purpose of this little game is to turn off all the lights. But the situation is a little bit more complicated than usual: if you press a button, the corresponding light and its two neighbors change their state. How many attempts do you need to turn off all lights?
Contributed by: Edda Eich-Soellner (University of Applied Sciences, Munich, Germany)
SNAPSHOTS
DETAILS
Hint: it is possible to turn off all the lights with at most seven clicks.