The game begins:

Three buildings (A, B, and C) sit next to each other on a city block and each buidling has three floors. On each floor, the lights are either on or off.

If you recognize this game (the game date is not specified) please explain the following:

In the explanation it says that B2 is always on, whether B has all 3 or just 2 lights on. My question is, why can't B1 and B3 be on with B2 off?

If I need to write out the whole game, let me know. It's driving me crazy!!