Linedef type 200, Light Block, is a type of floor over floor block which alters the light level in a specified area. The light block itself cannot be seen, only the flats, textures and Objects that are affected by it. It is useful for creating bottomless pits in which the light level fades as the player falls, which is achieved by stacking light blocks of progressively higher light levels above a death pit.
Setup
The floor height and ceiling height of the FOF are determined by the floor height and ceiling height of the control sector. The light level of the control sector determines the light level of the light block.
It is strongly recommended that light blocks touch or overlap at least one wall or flat within a sector. Otherwise, the light block's effect will not be noticeable until a player passes through it, which is unrealistic because the light will not have any visible source or surface to reflect on.