Puzzle 56: Turn on the Lights
Toad Hall at OMG University is illuminated by a 4 × 4 array of powerful lights. There is a corresponding bank of 4 × 4 switches that are suppose to turn each light off and on. All the lights are currently off and a porter has been sent to turn them on. This should be simple, but the electrics at Toad Hall were recently rewired by the Acme Electric Company. They are cheap, but they hire ex-comedians. Now when a switch is flipped, all neighbouring switches are inadvertently switched too.
To clarify possible confusions, if the switch corresponds to a boundary light, then there will be fewer than four neighbours. Also, by neighbour, we mean horizontal or vertical neighbour, not diagonal. Is it possible to get all of the lights on?
Extension: Can you do this with at 5 x 5 array?
To clarify possible confusions, if the switch corresponds to a boundary light, then there will be fewer than four neighbours. Also, by neighbour, we mean horizontal or vertical neighbour, not diagonal. Is it possible to get all of the lights on?
Extension: Can you do this with at 5 x 5 array?