- Each white hex must contain either a red, green or blue light bulb.
- Light bulbs of the same color cannot be in neighboring hexes.
- Each white hex must be lit by all three colors of light (including those that already have light bulbs in them).
- Light travels away from light bulbs in six rays, one each through the six sides of the hex.
- Light continues in a straight line until it is blocked by a black wall hex.