Doom contains a limit on the number of platforms which can be moving simultaneously. A platform is defined as a sector with a moving floor. The limit in Vanilla Doom is 30. If the platform limit is exceeded, the game quits with the message "P_AddActivePlat: No more plats!". A simple way to deliberately trigger this error is to create a linedef to trigger a moving floor. If the linedef is given no tag (ie. a tag of 0), triggering it will attempt to cause every untagged sector in the level to start moving. On any reasonably sized level this will cause the limit to be exceeded.