Starting with the first exercise - the cylinders around an arbitrary minor axis - there are a few issues that jump out at me:

• Your minor axis corrections (the red lines) are often themselves not correct. As you can see here on your last page, many of these were off by varying amounts. This suggests that you may not have spent as much time analyzing your ellipses as you should have. Remember that the minor axis splits an ellipse into two equal, symmetrical halves, down its narrowest dimension. This means you should be able to fold an ellipse back over its minor axis line and have one half fall directly on top of the other. Scott Robertson demonstrates this in this youtube video.

• When drawing the sides of these freely rotated cylinders, you don't appear to be applying the ghosting method as thoroughly as you ought to, resulting in lines that wobble and waver somewhat. Remember that the ghosting method is key to maintaining both control and a confident, smooth execution. It's time consuming, but it is necessary and required throughout all of these lessons.

• Try and limit yourself to drawing through your ellipses two full times - no more, no less. When you draw through them too much you start to lose track of the specific ellipse you were trying to draw in the first place.

• There is still some unevenness and stiffness to some of your ellipses, so remember that the ghosting method can and should be used on ellipses as well - specifically to achieve control whilst maintaining a smooth, confident execution free from hesitation.

Another thing I noticed was that your cylinders tend to feature no real foreshortening - meaning you have both ends are being drawn roughly the same size (and in several cases, you're actually making the farther end larger which contradicts perspective altogether). One thing on this topic I leave students to try and determine for themselves is the relationship between the shift in scale of the far end (basically how the far end is supposed to get smaller than the closer end) and the shift in degree. Both of these happen together - as the far end gets smaller, the degree gets wider, and both of these properties tell the viewer that this end is getting farther away. So if the shift is more significant, it means the cylinder is very long. If the shift is minimal, then the cylinder is fairly short.

If however you end up with the scale not shifting at all, but the degree shifting, then that gives the viewer a contradiction, and they can usually pick up on something not quite looking right.

Moving onto your cylinders in boxes, this exercise is rather than being about cylinders themselves, it's actually a lot more about the boxes. Specifically, just like how we apply line extensions to see whether or not our lines are converging consistently towards their intended vanishing points, adding the cylinder portion actually allows us to test and improve upon our ability to draw boxes that have square faces. Not perfect cubes, but where one pair of opposing faces are actually squares in 3D space rather than just arbitrary rectangles.

By testing against the criteria for whether those ellipses are actually representing circles in 3D space (by checking the alignment of the minor axis and the alignment of the contact points) we can test whether or not the ellipse that fits within a given plane is actually a circle. If it's not, then it's less about the ellipse being drawn incorrectly, and more that its container is not a square. Therefore by pushing through this, in many ways you're able to develop an intuitive sense of how to construct more proportionally square boxes.

To this point, there were definitely areas where you didn't necessarily try to draw proper cylinders - for example, #97 was intentionally squished. Fortunately there weren't too many of these. Most of your cylinders were striving to be drawn with the correct proportions, and as such you improved on your ability to estimate the proper proportions for your boxes.

Now, I am most of all concerned about your minor axis issues in that first section, as well as with your foreshortening being shallow all of the time. As such, I am going to assign a few more. I'd like you to do 25 more cylinders. Make a point of varying the rate of foreshortening (some shallow, some more dramatic), and consider how this impacts both the scale shift of the far end, as well as the degree shift. Also, take more time in identifying your true minor axis.