2:58 PM, Wednesday July 15th 2020
I had to experiment a lot before getting it ( I think ). It's easier to try a lot of examples and see what looks right.
Break it down to the simplest example.
Draw a plane in space like in the earlier exercise. Draw a line that goes over the the top of it. Now start inking from one end of the line until it looks like it has reached the the plane. Stop there. That is a basic step of the exercise.
I think it is something that you need to keep trying, evaluating, and eventually something clicks. Rewatch the example videos too.
PS I now remember that I created a couple of A4 sheets of shapes. I then printed out several copies of each. I practiced on these until I managed to get the hang of it. You really have to use your brain to visualise.