Jumping right in with your form intersections, you're doing fairly well with these and demonstrating a solid grasp of the interactions between flat surfaces in 3D space - but you are running into some little issues when dealing with rounded surfaces, which is actually still pretty normal at this stage. I've marked out some corrections here.

It helps, when dealing with these intersection lines, to keep in mind that intersections do not occur between whole forms, but rather between the different surfaces present in their structure. It is not a matter of a form being rounded or flat - but rather its surfaces being so, resulting in forms that may feature both rounded surfaces and flat surfaces (line cones and cylinders).

So for example, looking at the box-cone intersection towards the upper right, here the intersection occurs primarily between the flat surface of the box, and the flat base of the cone (or at least I think I'm interpreting the orientation of the cone correctly, given that it's penetrating into the sphere below it, suggesting that the cone's base is facing the viewer). Thus, the intersection (or at least the majority of it) is a single flat line, defining the intersection between two flat surfaces.

This diagram helps explain how we can think of these intersections as this kind of interaction between faces, and while I feel that your work suggests that you already understand this to a point, I think the transition at the end where we take a sharp corner and turn it into a rounded one, it may help you to navigate intersections between different rounded surfaces. This is something we will take another look at in Lesson 7.

Continuing onto your object constructions, as a whole you've really knocked this one out of the park, with cases like this bottle being very strong examples showing clear understanding of the core principles of the lesson. In particular, your work and how you approach it demonstrates a high degree of precision, which is especially important to these last couple of lessons in the course.

Precision is often conflated with accuracy, but they're actually two different things (at least insofar as I use the terms here). Where accuracy speaks to how close you were to executing the mark you intended to, precision actually has nothing to do with putting the mark down on the page. It's about the steps you take beforehand to declare those intentions.

So for example, if we look at the ghosting method, when going through the planning phase of a straight line, we can place a start/end point down. This increases the precision of our drawing, by declaring what we intend to do. From there the mark may miss those points, or it may nail them, it may overshoot, or whatever else - but prior to any of that, we have declared our intent, explaining our thought process, and in so doing, ensuring that we ourselves are acting on that clearly defined intent, rather than just putting marks down and then figuring things out as we go.

Throughout your constructions here you focus heavily on achieving high precision primarily through your use of subdivision, effectively allowing yourself to separate the decision of the nature of the mark you wish to execute, from the step at which you actually make the mark. And so, you're able to focus all of your attention on executing a mark whose specific requirements have already been determined.

In the computer mouse demo, I introduce the use of orthographic plans, which can - though not so much as demonstrated there - be an exceptional tool for taking those "decision making" steps and pushing them farther back in the process, to even further improve the precision of how we approach it in the end. In that demo here I demonstrate taking a side and top view of the object and subdividing its bounding box into quadrants to get a rough approximation of how the different elements of the structure in each orthographic view relate to those different subdivisions.

This can however be taken further, and it's something that will be very useful in Lesson 7 - so I wanted to make sure to share it with you here. Eventually it will be present in the lesson material, but the overhaul I'm gradually working through is quite time consuming, so that won't be for a while. In the meantime I'm being sure to provide that information in my feedback for those on the official critique track.

If we take a look at the example from that demo, here we can see that it leaves a lot of landmarks that we ultimately still have to guess at. What we want to avoid is being at the stage of making the mark, and having to make a decision/estimation at that point. Doing what you did is far better - making the decisions as we subdivide our 3D box. What we can do however is make those decisions when first analyzing the object, in these kinds of orthographic plans, identifying each major landmark with a specific subdivision in order to pin down exactly how far along each proportion every such landmark should fall.

Keep in mind that this is not about discovering the accurate positioning of things. Rather, it's about making a decision that we will then stick with as we build up the structure. So in a case where we had a drawer, and the handle for that drawer spanned from the 19/50ths to the 31/50ths positions along its face, that would be a huuuge pain to subdivide. It wouldn't actually be that noticeable however if we simplified them to 2/5ths and 3/5ths respectively, as long as this "rounding" doesn't cause any important smaller elements to cease to exist (like in the case of something that spanned across from 19/50ths to 20/50ths, though such things would be pretty rare).

The point to all this is that the further back we push the decision making, especially with the kind of complex subject matter we deal with in Lesson 7, the better. Using orthographic plans in this manner basically allows us to make all those decisions up-front, and then simply follow an established formula when transferring those decisions into a 3D construction.

There may be situations where you find that you perhaps missed an important decision or two - in such cases you may opt to make those decisions with subdivisions in the 3D construction (in other words, how you appeared to work in your constructions here), or you can choose to go back to update the orthographic plans, making the decisions there, and then transferring it back into your construction.

It's less about right and wrong, and more about always working towards more precision rather than less.

So! Overall, very solid work. I can see your grasp of 3D space developing very nicely, so I'm happy to mark this lesson as complete.