簡單地說，這是一個N x N的棋盤（比如3x3），這個正方形棋盤橫著和豎著的格子數是一樣的。
We will look at an NxN board (3x3). The number of horizontal and vertical squares on the board are the same.
一開始的時候，每一個格子的燈全部是滅的，當你點擊其中一盞燈（一個小方格）的時候，「這個格子」+「上下左右四個格子」都會改變狀態（由亮變暗，或者由暗變亮），超出邊界的則忽略。
At the beginning, all of the lights in each grid are off. When you click one of the lights (a small grid), "this grid" + "up, down, left and right four grids" will change their state (from light to dark, or from dark to light), and those beyond its boundary will stay the same.
遊戲的要求是，你能以最少的步數，將全部的燈點亮。也就是變成下圖的樣子：
The aim of the game is to light all the lights with the minimum number of steps. Please see the following images:
比如，對於下圖中的N=3，點擊正中間的的黑色方格，會使得上下左右及中間這5個格子由暗變亮，如下圖所示：
For example, for N = 3 in the figure below, clicking the black square in the middle will make the five squares from top, bottom, left, right and the middle dark, as shown in the figure below:
再點擊左上角第一個方格，自身變亮，但是右邊和下面的方格又變回暗的（左邊和上面的格子超出範圍不考慮），如下圖所示：
Click the first grid in the upper left corner, and it will become bright, but the grid on the right and below will turn dark again (the grid on the left and above will not be considered if it is out of range). This is shown in the following figure:
這裡是線上的視頻遊戲，連結如下：
This is the online video game. The link is as follows:
https://www.geogebra.org/m/dRyWhGUq
如果小朋友們願意動手操作，也可以用9張大小相同，但是正反兩面顏色不一樣的紙，擺成這樣整齊的棋盤方格，然後自己嘗試下翻轉哦！
If the children are willing to try it, they can also use nine pieces of paper of the same size. But with different colours on both sides, put them into such a neat chessboard grid, and then try to turn it down by themselves!
當然啦，3x3的棋盤，也就是橫著3個格子，豎著3個格子的這種圖案是最簡單的啦！如果小朋友們解鎖了這一關，可以嘗試著挑戰格子數更多的棋盤，比如說4x4，5x5……
The 3x3 board is the simplest. If children can unlock this level, they can then try the challenge of larger boards with more squares, such as 4x4, 5x5 …
以下是更多挑戰的連結：
The following are links to more challenges:
https://www.geogebra.org/m/TETbjz7y
https://www.geogebra.org/m/YXt3VhPn
https://www.lightsout.ir/
數學的世界是不是很奇妙呢？聰明的你可以自己嘗試著探索下哦～如果關於這個遊戲你有很棒的想法或者玩法，也歡迎分享給我們：
mathsweek2020@rkcshz.cn
Isn’t the world of mathematics wonderful? Go ahead to explore it. If you have good ideas about this game, please share them with us:
mathsweek2020@rkcshz.cn