Shapes are drawn in an art package that can handle PCX pictures and then grabbed. The process is detailed in hextools. There has to be at least one World, and there can be up to 24, each holding up to 48 terrains and 32 gates - entrances to other worlds or other parts of the world. What actually happens on a cell is decided by other objects, but cells of the same value in the same map share the same Terrain. The graphics in the map generators are mnemonics for properties I have decided on, and can be changed with a PCX editor.
Any item can have a picture associated with it.
Some pictures are used for default situations like camping or looting. Each world also has a background picture on which the shapes are drawn. A collection of pictures. 99 general pictures are allowed, the biggest single diskspace user in the game, but only 13 backgrounds. Only one of each is in memory at a time.