LIGHTS OUT

• Click to Toggle: When you click any tile, it and its adjacent tiles (up, down, left, and right, if they exist) will change state simultaneously.
• State Change: Lit tiles turn off, and unlit tiles turn on.
• Goal: Turn off all the tiles on the board through a clever sequence of clicks.

While random clicking might occasionally work, for higher difficulty levels (such as 5 × 5 and above), you need to master a classic algorithm called “Chasing the Lights”:

Step 1: Chase from Top to Bottom

Start from the first row. If there are any lit tiles in the first row, click the tiles directly below them (in the second row). This will turn off the lights in the first row.

Then repeat this process for the second row, third row, and so on, pushing all the lit tiles down to the last row.

Step 2: Handle the Last Row

After completing Step 1, there will usually be some lights remaining in the last row. At this point, you need to click specific tiles in the first row based on the pattern of the remaining lights.

For the classic 5 × 5 grid, there are some well-known patterns:

If lights remain at positions 1 and 2 in the last row: click position 2 in the first row.

If lights remain at positions 1 and 5 in the last row: click positions 1 and 2 in the first row.

If lights remain at positions 2 and 4 in the last row: click positions 2 and 5 in the first row.

After performing these compensating clicks in the first row, repeat the “chasing from top to bottom” process, and all the lights will be turned off!