During 0-1 each task completes its initiate.

During 1-2
   Task 1 completes its request (i.e., the request is granted).
   Task 2 completes its request (i.e., the request is granted).
Two items available at 2.

During 2-3
   Task 1 releases 1 unit (available at 3) and terminates at 3.
   Task 2 releases 1 unit (available at 3) and terminates at 3.
Four item available at 3.