Misleading parts of the "Go-back-n : example" image

[leonardomaccari]

The last two windows in the left column are not well aligned. When DATA.req(d) happens, the next window should have a red "3" but it stays green, and it becomes red after no event has fired.
It would also be nice to write next to the sender windows the values of the unack and seq variables as described in the SM.

Finally the last sentence is misleading "e will be accepted and sent later" is interpreted as "e will be accepted, and sent later". I would rephrase with "e is dropped, the application will eventually retry to send it later on. "