Push the buttons and the effect will surprise you.
Only if all lamps are on, you can cheer.
The puzzle consists of a system of buttons and lamps. Each button effects a different count of different lamps. To push or to release a button causes a change of the state of all lamps, which are connected to that button. The point of the puzzle is to find out the state of all buttons so that all lamps are lighted. Every button can be locked, if you believe to know its correct state. With this you can protect it for unindentional operation. You can vary the count of buttons from 4 to 25 and with it the difficulty.