TYPE 3 PROHIBITED LAMP(S)

Type 3 Prohibited Lamp(s)

The single highlighted cell draws your attention to the Prohibited Lamp Cell at C7-R6. This cell is not yet illuminated, and is not permitted to contain a lamp, so it must be illuminated by some other lamp. It is easy to see that there are exactly two cells which could complete this task, viz. C7-R5 and C8-R6. Regardless of which of these cells contain the lamp, the highlighted cell will be illuminated by it. This being the case, it qualifies as a Prohibited Lamp