Each piece has a list of properties. Characters have full size and width. Torches can be lit/unlit or have it´s fire increased or decreased. Doors have options to be made of wood or iron, and to be fully opened or partially opened. Grates can be reversed into arches, enemies can have weapon changes, all of this is accomplished by properties. Also every architectural piece has an environment. That way you can have white marble tiles surrounded by green marble tiles, for instance. And everything can be done during a game session. Lit torches, open doors, transform a little goblin into a giant…