It is probably easier to make an analogy between the courses of the planets, and two trains travelling in the same direction.将行星的运行比作两列火车朝同一方向行驶可能更容易些。All planets travel in the same direction.所有行星都朝同一方向运行。Colouring is done in the same direction but with the strokes in reverse order.着色是朝着同一方向的，但线条则是反向勾勒的。