Rollback?

What exactly is a rollback and how do you do it?

Because I can't explain anything:
http://www.youtube.com/watch?v=U7Pm3nXy7QA

Or if your western rollback:
http://www.youtube.com/watch?v=HqkZmmj8puw

I see a noticeable difference but my mom says they are the same. 8)

A roll back in jumping is when there are 2 fences next to each other and you jump one turn and jump the other one. Sometimes they are set on diagonals and jump one turn and jump the other one. Or they can be set straight on.

Here is a video the first two jumps she does is considered a roll back
http://www.youtube.com/watch?v=XVGWYX4c0Rw

Oh I get it. Kinda like a u-turn. That's what it should be called. Less confusing.