"But Abalisk!" you might ask, "If that's the intermediate exercise, then what about ones for beginners? How am I supposed to draw a shop vac anyway?!"
I'm so very glad you hypothetically asked this question, because I'm gonna share with you something that blew my third eye WIDE OPEN when it was told to me by my instructors. It literally changed the way I see the world and I've never been the same since...
The secret ingredient and quite literally the fundamental core of all things are these three simple words:
Mother. Fucking. Geometry.
More specifically the Triangle, Square, and Circle in various configurations and dimensions. And no, I am not shitting you. I'm being perfectly serious.
Because one of the things that is usually missing from a lot of "learn how to draw" books (i had a few of them as a kid too) is this rule and really is the main reason why the joke "now draw the rest of the fucking owl" is so on point. They aren't building you up properly so that you can have a strong foundation for your art and this is generally why people perceive drawing as some difficult achievement that only a select few are capable of.
But this is not true. Anyone can draw and anyone can build the skills they need to view the world through this geometric lens. It just takes practice.
And believe me, I was skeptical too until my instructor literally sat down and showed us an example.
Clip Studio goes into further detail here, but basically as you can see here with this dog, when broken down to its core shapes, is mostly a series of circles and rectangles (and for me personally they could have done a better job in breaking down the leg joints but that's a personal pet peeve).
The same can be done for humans, albeit we're a lot more complex... More so than a shop vac anyway lol (and here is an example of my own human anatomy work from my college days):
So many cylinders (which is just an extruded circle btw).... but as you can see the point is to break down what you see into simple shapes, because in doing so you simplify the entire process. Understanding shape and applying it to your understanding of the world makes the task of replicating that image into something you can make with your own hands SO much simpler.
And eventually you'll be able to draw the form without going into too much detail on the shapes.
Remember what I said earlier? You know, about "building a solid foundation?"
That's right, baby, drawing and drawing WELL is just glorified Building Blocks. You're WELCOME.
As for the art exercise, just take your object and draw it in as simple shapes as possible. Then once you've accomplished that, try to add more complexity in subsequent iterations.
Does this mean you're gonna be drawing a shop vac a whole bunch of times? You betchur ass it does!
But by God you'll know that shop vac by heart in the end and THAT my friend is the goal. Repetition paves the way to understanding. And understanding is what allows you to make and break the rules later >:)c