I wish I had uploaded this in a larger version. Maybe I'll do that later.
I tried to cram a bunch of stuff in the drawing. You have Gothmog on his dragon in the foreground with dead Gondolin elves burning nearby. Surrounding Gondolin are the legions of Morgoth. Notice the siege weaponry I added in that includes trolls manning catapults and on the right a giant siege hook pulled by both trolls and non-flying dragons. On the battlements of Gondolin the elves have ballistas. Notice the "G" runes I added to the walls and the gate (I'm guessing the last, steel gate).