Nod nod. {spider makes cobweb, cobweb is ingredient in thread, thread is ingredient in cloth, cloth is ingredient in bed!}

"Do the spiders make cobwebs on their own such that I can find some and steal them, or do I need to interact with the spider directly?"

{not sure. maybe ask stone spirit?}

"Fair enough. The stone spirit is underground somewhere, right? Do you know where in more detail or should I just expand my tunnels some more until I find them?" The latter sounds like a very slow process, but digging tunnels is oddly fun when it's this easy and the results are this rectilinear.

{stone spirit in cave probably. don't know where. i think on this island though!}

"Okay. Do you want to go looking around caves together?"

Bounce bounce. {yeah!!}

"Awesome. We can start with the one I found last time I was mining, since it's the only one I know where it is." 

Time to go down a hole!

The forest spirit perches on his shoulder as they descend.

Inside the cave, there is dirt and rock and a large craggy grey slime bouncing aimlessly around.

Can he see the entire cave from here, or are there places where it goes around a corner or beyond the range of his torch?

The torch illuminates a significant amount of cave, but the far end is still dim when he stands just outside and peers in.

Then he'll go explore the far end, keeping a wall immediately on his right in case it gets twisty.

The fundamental orthogonality of the universe means that it's hard for a cave to get that twisty, since all the walls are made out of identically sized cubes and part-cubes. That being said, it's still a cave, and within its constraints it does indeed attempt to twist.

At the far end of the cave, there is a right-angled bend and a descent of one cube-height into a narrower corridor, where a rocky little dude is trundling toward Bruce from a deeper dimmer area.

{hey there,} says a deep gruff spirit-voice like stone grinding against stone. {careful. there's monsters down here.}

"Oh, hello!" Bruce says quietly. "Are you the stone spirit? I'm Bruce and this is the forest spirit."

{that's me,} the spirit agrees. {nice meeting you both. met anybody else yet?}