Granular question

Mattebass's icon
Max Patch
Copy patch and select New From Clipboard in Max.

Hello, I've been looking around for granular synthesis patches, and a friend gave me the classical Granular 2.5
I've studied it, and I think It's ok;
Not satisfied I've looked to some tutorials on youtube and I've come across to the patch attached:
a play object in witch I've both a line and a phasor. It seem, even if grossly, functioning, but I can't understand why from the point of view of the signals. Someone could help me.
Thanks

Matteo