Do we know if he was consciously using perspective here rather than working very accurately from observation? Ok I realise that water is a moving target, so to speak, but if you look at it closely for long enough you can get an idea of how it arranges in space over time. Much of the skill then is distilling the essence of these dynamics into a representation that makes sense to the observer. Obviously, you have presented this as part of a perspective course and I don't doubt your analysis, but the purpose of perspective is to accurately represent the 3D world on a 2D surface. So I assume that it is possible that an artist sufficiently skilled in accurate observation could produce perspective views without relying on formal perspective techniques.

I tried the level 2 drawings, which didn't go so well, to much redrawing and erasing. Lines nor really confident. I also tried to put too much detail in the skull.

My attempts at the level 1 drawings in this lesson, the snail ean't too bad, but the boot laces nearly drove me insane.

Here is my attempt ay both the pear and portrait. I had a go at both, as you can see I went some way towards simplification, but didn't fully get there by any means.

I am very likely to purchase the head and figure drawing courses, but am unsure about this course which is quite a bit more expensive. I can see that it would be very useful for more advanced human figure drawing. However, my main interest is in animal drawing, would the techniques learned in this course be helpful in that arena? Obviously the specific anatomies will differ, except possibly for primates, but would there be enough general techniques in learning anatomy to justify buying the course? I should say that I have signed up for Aaron Blaise animal drawing courses so this would be in addition to those.