How do I identify rough-in plumbing pipes?

Question

I have just bought a house, and we are looking into finishing the basement, to help with design ideas, i'm looking into what the bathroom will be.

The rough-in pipes are in an odd placement in the basement, and not really sure how I would go about designing a bathroom but attached is a picture of the rough-ins (On the left)

I'm hoping someone can help me identify what these pipes are:

1.) Floor to ceiling pipe with valve sticking out.

2.) Around 4" pipe in far corner

3.) Around 6" pipe in between those two, about 4' from the left wall.

Answer 1

Closet to the corner against wall is for a shower or bath drain. The next is toilet drain. The next is where you attach the sink drain.

The fourth (closest to camera) is the main stack for the house, with the main line clean out at the bottom.