Linedef type 160, Water Bobbing, is a type of floor over floor platform which will float in water, and bob up and down if the player jumps on it. If this FOF is placed above a water block, it will fall into the water by itself. This FOF is affected by gravity while it is outside the water. For example, if the global gravity is lower than 0, the FOF will float upwards, out and away from the water.
If the water level moves below the sector floor by use of linedef executors, the floating FOF will come to rest on the sector floor, and will resume floating and bobbing if the water level comes back up. However, while it is in water, it can bob below the sector floor if jumped on with enough force, and the water is shallow. Its floor and ceiling heights will actually become warped if such an event happens.
Bear in mind the gravity will only affect this FOF if the sector inside it actually contains a water block; if this FOF placed in a sector with no water, it will behave as a stationary floating platform, exactly like linedef type 100.
Setup
The flats, floor height, and ceiling height of the FOF are determined by the flats, floor height, and ceiling height of the control sector, and the sidedefs of the FOF's walls are determined by the sidedef of the control linedef.
The light level of the control sector will determine the brightness of the shadow cast by the FOF. If the light level of the control sector is lower than that of the target sector, then it will cast a dark shadow. If the light level of the control sector is higher than that of the target sector, then the FOF will illuminate the area below it. If the light level of the control sector is equal to that of the target sector, then the FOF will not affect the light of the area below it.