generative art in unity

If i want to arrange cubes and cylinders into patterns, spirals, etc, and instantiate 1000/10 000 of them in one run, is it possible?

say i wanted to make space invaders like this out of tubes:

what is the least computationally expensive way to do it, regarding colliders, instantiation, etc?

Yes it should be. I would make a prefab and instantiate prefabs. If you have some groups of patterns that get repeated, you could prefab them too. Depending on what you’re doing, you may want to run a ‘combine mesh’ script on them to cut down on draw calls.