The question that you asked is kind of confusing but I think that I have it.
Step-by-step explanation:
So, as you said Marvin moves by a 1 by 1. 1 to the right and then 1 up. But there is an obstacle at (4,3). To evade that obstacle I would suggest going up four, and then over 1. To be honest, there are a ton of ways. All you have to do is just steer clear of (4,3).
