Super Weapons Of The Ancient World - The Ram.
Basically they told anyone who said "across this line you DO NOT...," fuck you, this is Nam, there's no fucking rules, cry babies!
;D Hell of a way to knock on the door.............
YouTube vid here - http://www.youtube.com/watch?v=1WQadRChjik&feature=related
(http://www.preteristarchive.com/JewishWars/images/assault_walls/ram.jpg)