if (length < 0) return new int[0];
	private int[] computePolyline(Point left, Point right, int height) {				final int WIDTH= 4; // must be even		final int HEIGHT= 2; // can be any number				int leftX= left.x;		int peeks= (right.x - left.x) / WIDTH;						// compute (number of point) * 2		int length= ((2 * peeks) + 1) * 2;		int[] coordinates= new int[length];				// cache peeks' y-coordinates		int bottom= left.y + height - 1;		int top= bottom - HEIGHT;				// populate array with peek coordinates		for (int i= 0; i < peeks; i++) {			int index= 4 * i;			coordinates[index]= leftX + (WIDTH * i);			coordinates[index+1]= bottom;			coordinates[index+2]= coordinates[index] + WIDTH/2;			coordinates[index+3]= top;		}				// the last down flank is missing		coordinates[length-2]= left.x + (WIDTH * peeks);		coordinates[length-1]= bottom;				return coordinates;	}