Using Yahoo Pipes to Convert an RSS feed into iCal

Question

I'm looking at the Yahoo Pipe http://pipes.yahoo.com/pipes/pipe.info?%5Fid=tI17l5t63hGwcq4a0EypaA as the basis for converting RSS feeds into iCal format. Looking at the Pipe design, I've got the following questions:

1. The 2nd Loop construct assigns item.dtstart to item.y:dtstart:

I realize this is a basic question, but the meaning of "item." vs. "item.y" is not clear to me. I'd like to understand this.

1. The 3rd Loop construct assigns item.dtend.dtend to item.y.dtend. Why isn't the source "item.dtend" vs "item.dtend.dtend"? The next step in the pipe renames item.dtend.dtend to just "dtend" so this further confuses me.

Thanks in advance.