timer-triggered This fact checks whether a given timer has triggered. For disabled timers this fact is always false. The check can be performed any number of times until the timer is explicitly disabled. town-under-attack This fact is set to true when a computer player’s town is under attack. unit-available The fact checks that the unit is available to the computer player's civ, and that the tech tree prerequisites for training the unit are met. The fact does not check whether the unit training can start. This depends on resource availability, housing headroom, and whether the building needed for training is currently used for research/training of another unit. The fact allows the use of unit line wildcard parameters for the . unit-count This fact checks the computer player's unit count. Only trained units are included. unit-count-total This fact checks the computer player's total unit count. The total includes trained and queued units. unit-type-count This fact checks the computer player's unit count. Only trained units of the given type are included. The fact allows the use of unit line wildcard parameters for the . unit-type-count-total This fact checks the computer player's total unit count. The total includes trained and queued units of the given type. The fact allows the use of unit line wildcard parameters for the . victory-condition This fact checks the game victory condition. wall-completed-percentage This fact checks the completion percentage for a given perimeter wall. Trees and other destructible natural barriers are included and count as completed. wall-invisible-percentage This fact checks what percentage of the potential wall placement is covered with fog. Example: (defrule (wall-completed-percentage 1 < 100) ; Not all of it finished (wall-invisible-percentage 1 == 0) ; And we