public Wall getInSquare(Set<Wall> usedWalls) {
        if (north.equals(east) && north.equals(south) && north.equals(west) && north.wallType.equals(WallType.SquarePart)) {
            usedWalls.add(north);
            usedWalls.add(east);
            usedWalls.add(south);
            usedWalls.add(west);
            return north;
        }
        return null;
    }