scroll and pin elements on screen

[donini]

Hi! I need an approach like this:

according the session of screen i'm, I need to leave some pin elements on the screen, and when I scroll back, this element need to be unpin, anyone have a idea?

I need this to assemble a shoe, as it scroll down the parts of shoe will fall attaching overlaying, and as it rolls up, will detaching.

[karneaud]

+1