Let us choose the amount a DL wall obstructs the view behind it. Additionally, let us change the color this "shadow" would cast on the map. This would be useful for several things: Marking cover objects for a defense bonus Making windows or other small, impassable openings Making secret doors that require a RL spot check ;P (Set opacity to 99% on a small section, if your players are too tired to look at the map closely, too bad...) There are probably many other use cases I've not thought about, but this is the basic idea.