public static Direction getOppositeDirection(Direction d) {
		switch(d) {
		case SOUTHWEST : return NORTHEAST;
		case SOUTH : return NORTH;
		case SOUTHEAST : return NORTHWEST;
		case WEST : return EAST;
		case NONE : return NONE;
		case EAST : return WEST;
		case NORTHWEST : return SOUTHEAST;
		case NORTH : return SOUTH;
		case NORTHEAST : return NORTHWEST;
		}
		return NONE;
	}