Rules: The challenge is to light up all white cells, subject to the following rules:
- Each lit cell illuminates all white cells in a horizontal and vertical direction until the beam hits a black cell or a wall.
- Lights are of one of three primary colours, red, blue and yellow with their beams shining a light of that colour.
- Numbers dictate how many cells horizontally or vertically adjacent to the cell have lights.
- The colour dictate the colours of the co-responding bulbs, if it is a primary colour then only a bulb of that colour may be adjacent to it. If it is a secondary colour then it must have bulbs of two co-responding colours adjacent to it, red and blue for purple, red and yellow for orange and blue and yellow for green.
- Beams of the same colour may not occupy the same square, however, beams of separate colours are free to mix.