This type of light flickers randomly to simulate a broken light. Check the "References - FAQ" section for details on the technicalities of lighting effects.

Create the sector which will flicker randomly with brightness. The shade of the sector will show when the light is off. It is sensible to texture the ceiling with broken lights. Place an S[RandomFlashNumber,4] in the sectors which will flicker. The shade of the S determines the appearance of the sectors when the light is on. You can use any value for RandomFlashNumber, but be sure it is unique from any other flickering lights in the map. Two lights using the same RandomFlashNumber will flash simultaneously.

Note: Flickering Lights swap the effect of palettes. The palette of the sector will show when the light is on, and the palette of the S determines the appearance of the sectors when the light is off.