how to build webpage of growing length by cocoon

[Lechael Han]

Basically I want to create a page of growing length. For example, first user select an item H from a droping list and then select some attributes for Item H, Then user selects item B then select some attributes for item B. and so on.... I want a page with user's selections  up to now, as well as  future possible choices in a droping list   Then here is my question 1, I think some kind of loop is necessary in the pipeline.  am I right? Is there some kind of component in cocoon that can do this? 2. Or this can be done by several pipelines working together, but this way,   how can cocoon know the number of elements, and the number of attributes in every element  in the page up to now?   Thanks for your kind help! Thanks