Obviously this is a different skill altogether, because they move all the time!
The result was that I had to use very few lines, and also that most of the page is filled with partial figures.
By the second page, I was trying more to get the shape of the person from where I was sitting, rather than the detail. That meant that in some places there were blocks of shading or only the wrinkles in the trousers. The teacher had a
Lastly, I drew a boy in a seat in front of me who was taking off his skates and talking to his brother at the same time. Again, it was tricky to get his head and hands right when he kept moving them! I rather liked the way the boot took over and became huge, as that was the centre of attention.