Here's an answer to a question I posted (It's down in the comments)
Derived from this video
The only thing missing is the ability to Boolean the spheres, cubes, cylinders.
I think that involves realizing instances via the Realize Instances node, but, it's not covered in the tutorial, and nothing I've tried works.
This is what it looks like before and after attempting to apply a boolean Difference.
This is me attempting to apply a boolean (Difference)
What it should look like if it worked (imagine it all around) instead of just the top face: