Walls only come in hue 0. None of the walls can be stacked, dyed, or rotated. Just like with the house customizing tool, each type of wall only comes in certain types, and most are incomplete sets. However, south and west facing walls can be overlapped to create south-east corners, and plain north-west corner pieces work for all wall types, as only the top of that piece is normally visible. Rubble walls also will not hide when circle of transparency is used, therefore be careful 'hiding' items behind them in your house layout.
A palisade is a fence or wall made from wooden stakes or tree trunks and used as a defensive structure. These pieces came from the barricades set up during the course of the event. There are two types of full-height walls; those with spikes at the top, and those without.