The li'l piece of wall to the left is made out polyurethan foam, which Sarah carved bricks in and painted. The wee bit larger piece of wall to the right is made out of polystyrene. Once again she carved bricks in it and painted it.
We have talked about using both materials for background buildings... ...for maxium efficiency! (depending on just HOW decayed we want the buildings to be).
We also talked about making the actual wall (surrounding the ghetto) out of small plaster bricks and then creating the wall like you would a REAL one. This is to get the right look of the wall; which would be hard to get by carving the bricks in some sort of material (like the background buildings).