First attempt at describing our LOS rules for this terrain board:
WRT this illustration:
1) By default, we conceive of our desert game map as a basically flat surface with gradual minor elevations and depressions. Although in reality elevation changes would be smooth and gradual, for simplicity we model them with contour lines as in a 1970s tactical board game map.
2) Game elements can be either at ground level, or on hills. Elements on hills can be either on top of the hill or on the "hull down" line of the hill; both of these are "on" hills. The hull down line is defined as the hexes around the perimeter of a hill, adjacent to and below the boundary hill top hexes.
3) Elements at ground level have no LOS (line of sight) to elements beyond that hill.
4) Elements on a hill have LOS to elements on and beyond that hill, and to elements on other hills, but not to ground-level elements beyond other hills.
5) A hull-down defensive bonus accrues to elements on the hull down line, which are fired on along an LOS passing over their hill. The single exception to this bonus is if the firer is on the same hill as the target hull-down element.
Examples:
1) In the "desert_sighting_illustration_annotated.jpg" image, we have 5 Arab tanks on the left and 2 Israeli tanks on the right. Based on the rules above:
2) Tank 5 has no LOS to any enemy tank.
3) Tanks 1-4 and tank a are all "on" hills, and all have LOS to each other. Furthermore, Tank 1 has LOS to tank b, which is "beyond" the hill which tank 1 is "on".
4) Tank 4 has a hull-down bonus relative to tank a. Tank a has a hull-down bonus relative to tanks 2-4. Tank 1 has a hull-down bonus relative to tank b.
5) Tank a has no hull-down bonus relative to tank 1, and vice versa, as both are "on" the same hill.
MH