The Power Grid at TG-88.3Ω is reasonably advanced, if somewhat obscure. It is based on a 20th century logic puzzle called a ‘nonogram’.
When a square is turned on, it is light. When the facility is drawing full power, all squares will be light. Some squares must always be allowed to remain light, but in order to save power, as many light squares should be turned off as possible.
When a tile is turned off, it goes dark. Squares that should never be turned off are marked with a dot.
The numbers around the power grid matrix indicate how many squares in a row or column may be turned off.
For example, a row may be marked ‘4,4’. This indicates that eight squares in that row should be darkened. However, the two clusters must have at least one light square between them.
Squares with Dots
Squares with dots are exactly the same as light squares. The dots are simply an indicator that the square should not be darkened.
It is a good idea to mark squares that you are sure should not be darkened with a dot, to remind yourself.