One of the "security measures" of the Berlin walls. If someone runs over the trip wire, a launcher filled with rockets ignites. This allows guards who are further away to notice the attacker.
Rockets are built like this: http://minecraft-de.gamepedia.com/Feuerwerksrakete
A nice idea for RPG servers. However, the execution could be better, ie, the throwers could be less easily visible obstructed, the wall could look better.
Neutral evaluation
The wall and the conspicuousness of the launchers is beside the point. It's about the "rocket launchers"
Nice, I have combined this idea with a mob trap. But since Minecraft doesn't work for some reason, I can't post a screen.
I really don't have any ideas... That's just two launchers that are activated with hooks...