Lights Out up to 20x20
This activity belongs to the GeoGebra book Lights Out (Games with solutions).
Your goal is to turn off all the lights. The difficulty is that when you click on any square, in addition to its state, it changes the state of its adjacent squares.
You can choose up to 7 different states of lights and expand the board up to 20 rows by 20 columns.
1. First you have to establish the puzzle to solve. You can do it manually, coloring the boxes as you wish. Please note that your configuration may not be solvable. You can also choose to have the application Randomly color the board. In this case, the existence of a solution is guaranteed.
2. Afterwards you can try to solve the puzzle, that is, turn off all the lights. If you succeed, a congratulations message will appear.
3. Finally, you can see all the solutions of the proposed puzzle.
You can find more information about this game in this article (June 2002) of Suma magazine (Spanish magazine on the teaching and learning of mathematics).
Author of the construction of GeoGebra: Rafael Losada