I skimmed through this last night, but I won't be reading it again - this is honestly not an effective way to get questions answered, because those questions easily get lost amidst all of the rest. I understand the need to vent, but that's not the purpose this resource is meant to serve, and as we are already pinched between extremely limited resources (all of the official critiques are subsidized, with us paying up to twice as much to the TAs who provide the feedback, relying on those credits that are allowed to expire to balance things out as explained here) and a mountain of work, it's simply unreasonable to dump all that out here. Of course you did mention multiple times that I didn't have to feel pressured to answer - but you're basically putting me between the rock and a hard place of leaving a student openly struggling with something, or reading through a novel.

Now the one question I did pick up on was your confusion as to what "design" means. To design is to actively choose how something should be (in this case, the actual shape itself). That is to say, we're not pulling the information directly from the reference and striving to match it perfectly - the reference image is a source of information from which we are pulling information on what textural forms are present and how they're arranged, so we can then use that information to craft our gradient.

The first box on the left where we do a study, there students can do whatever they like to help themselves analyze the texture. Where the implicit markmaking comes in, is when we're actually crafting the gradient based on that information.

Lastly, in regards to the bubbles texture, you do get to choose which textures you tackle for the exercise. There's no specific benefit to picking ones that are especially challenging, because the base problem (whether your reference is simple or complex) is still the same as it is for the entire course. It's about understanding the relationships between the forms and the surfaces around them in 3D space. The reason we employ implicit markmaking here is that it is not always possible to draw everything explicitly as this can create a ton of contrast in sections of the image, turning them into focal points that draw the viewer's eye - whether you want it to or not.

Learning the mechanics of working implicitly gives us the freedom to control how much contrast a particular part of the drawing carries, so that the nature of what we're drawing does not have to dictate the way in which the viewer engages with our drawing of it.

I hope that helps - if it doesn't, then hopefully the newer material pertaining to texture that we'll be releasing in the coming months (once the overhaul reaches into Lesson 2) will help more.