generic geomorphic mapboards, each of which can be aligned to any edge of the same length to any other mapboard (except river boards). This allows for an almost unlimited number of combinations to create any terrain situation, including player designed scenarios. Printed overlays, first introduced in the gamette GI: Anvil of Victory, enable additional terrain types to be added to mapboards. Line of sight (LOS) is determined by sighting between the dots in the center of each hex. String can be used to check LOS, and the printed terrain depictions on the photo-realistic maps are used to determine blockages (hexes are not considered automatically filled by terrain therein). These LOS rules were innovative for board games when introduced in the 1970s. The original game contains mapboards mounted on heavy durable cardboard, which was (and remains) expensive but a design feature long associated with Avalon Hill games. Each mapboard measures 10 columns of hexes high by 32 hexes wide, numbered from hex A1 in the top left corner to hex GG10 in the lower right. The design philosophy that John Hill brought to Squad Leader was "design for effect". He hypothesized that no matter what kind of fire might be brought on a squad of infantry, be it a flame weapon, a grenade, a machine gun, or an artillery shell, there could only be three outcomes; the squad would be eliminated by killing or wounding the men in it; the squad would be "discomfited" to some degree (i.e. they must check for morale - if they fail they run for cover until rallied by a leader, and if they fail a second morale roll while "broken" the counter is removed as the men are assumed to have run away); or there would be no effect. Using this principle, he was able to employ a single table to create combat results of the various weapons systems used in the game. A similar principle is employed in dealing with support weapons - rolling a certain number might cause a weapon (e.g. a machine gun) to be put out of action, after which a player must roll again each turn until the weapon is either restored to use or lost altogether; there is no need to determine whether the weapon was broken, jammed, or was simply reloading with fresh ammunition.Squad Leader is a game system by design rather than just one game. The game