The upstairs hallway. We added some molding. Used 4ft by 2 inch precut wood. $3.00 for each one. Then cut them to make the right squares for the walls. Used a nail gun to hang them ,caulked and painted it the same as the wall.
I am not to sure about just having the 4 pictures on each wall but I didn't want it to look so full you can't see the squares but now I fear they look to naked.