Light Up Rules

Light Up is a fun game; here are the rules of play:

• Light bulbs need to be placed in the playing grid, in order to satisfy the following rules.
• A light bulb can only be placed in a white square. A white number in a coloured square tells you how many light bulbs must be placed directly adjacent to it in the solution
• Coloured squares that do not contain a number mean that you yourself must determine how many bulbs are placed next to that square, from 0 to 4
• When placed, a bulb highlights everything in its path both horizontally and vertically, unless it hits a coloured square which it cannot penetrate. If you are familiar with chess, it replicates the moves available to the castle, or rook
• The light from one bulb should not hit another directly
• In the solution, every white square must be lit, and the bulb placement must match the above rules

How to use our Light Up player

We have developed a fun player for you to use to enjoy Light Up online. Note that you may need Internet Explorer to fully enjoy the player. Here's how to use the player:

• To mark a square that cannot contain a bulb, press the 'X' key. If you make a mistake, simply delete your X.
• To place a bulb, press the 'O' key ('O' looks a little like a light bulb!) If you mistakenly place a light bulb, simply press the 'O' key in that cell again to delete the bulb
• To keep track of which squares are lit, you can press the 'l' key ('l' for light) in any square to make it turn yellow, to show that it is lit. If a cell is no longer lit, simply press 'l' again to return to its normal state
• If you go wrong, click 'Reset grid' to start again
• To check your solution, click 'Check My Solution' which will tell you if you are right or not, without revealing the solution
• If you give up, then click 'View Solution' and the player will display the solution in the grid.