water.wad 
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Effect demonstrated: - Swimmable water
a) Make a dummy sector. (A dummy sector is just a little sector not connected to anything else in case you were wondering).
This dummy sector will have a sector type of 4466 (EDGEs prefab Swimmable water sector type).
The lighting level (and blink effects) control those we'll see when we're underneath the water.
One of the lines of this dummy sector should be of type 404 (EDGEs prefab Liquid extrafloor). Give this line a tag number(for example 108).
Now, the floor height of the dummy sector will be the water level(i.e. the top of the water). Lets make it -8. This will make any sector tagged to 108 (the line we defined earlier) with a floor height BELOW -8 be a pool of water. The ceiling height can be anything higher than the floor height.
b) Now place a sector where you want the water pool to appear in the map and tag this sector to the line defined earlier(108). This new sector should have a floor height LESS than what you have defined in the dummy sector, otherwise the "hole" won't reach the underlying water level. Let's make it -104 deep.
