The Healing Pool - from The QuakeLab - Steve Fukuda

The QuakeLab - http://www.in2nett.com/stevefu/QuakeLab

        TEXTURES:

        Any WATER or the *TELEPORT texture.

        MAIN ENTITIES:

        trigger_once, trigger_counter, item_health

        WHAT TO DO:

        Make a room with a pool of water. Ensure that the surface of the
        pool is just high enough to conceal the health powerups that will
        fill the pool. Make a trigger_once entity. Give it a 'dummy' target
        so that you don't receive 'unassigned target' messages while
        compiling or running. This dummy target can be a torch (which will
        not react in any way to a trigger.) Give the dummy entity a
        targetname (dummy will do just fine.) Give the trigger_once entity
        a 'message' which reads 'You have found a healing pool!'

        Next, make a trigger_counter entity. Set its 'count' field to
        the number of health powerups you wish to place in the pool. Give
        it a targetname. Place item_health entities (health powerups) in
        the pool and set their 'target' fields to the 'targetname' of the
        trigger_counter. Set the 'nomessage' flag of the trigger_counter
        to the 'on' position. Otherwise, the player will receive messages
        such as 'Only two more to go!' and so on. Set the 'message' field
        of the trigger counter to read 'You have drained the pool of all
        its powers.' When the final powerup is picked up, the counter will
        be triggered and will display this message.

        NOTES/COMMENTS:

        A rocket launcher (weapon_rocketlauncher) has been placed in the
        demo map so that you can damage yourself before entering the pool.

        You could make a func_illusionary entity which would make solid
        ground passable. Powerups could therefore be hidden within apparently
        solid floors. Something to ponder, at any rate...