When being seiged by goblins I noticed a curious behaviour, when a goblin from a squad gets trapped in a cage trap and there are no dwarves or pets around to torment, the squad will stop dead in its tracks and cluster around their trapped squadmate. Through dwarven ingenuity we can exploit this behaviour by placing a single cage trap surrounded by 8 weapon traps like so:
+++++++
++^^^++
++^c^++
++^^^++
+++++++
+ = floor
^ = weapon trap
c = cage trap
As the trapped goblin sits in its cage its friends are eviscerated around him. Placing the cage trap centre on a tile that goblins are most likely to pathfind through enhances the effectiveness like so:
W+++W+++W
W+++W+++W
W++^W^++W
W++^c^++W
W++^^^++W
WWWWWWW
W = wall
Problems with this design include weapon traps becoming jammed (esp. serrated disks, you need the traps to continue reloading and firing as the enemies mill around the central cage trap), and the trap can only be used against one squad before the cage trap must be reloaded. Even after a seige expires the trapped squad will remain, so if all your traps become jammed and a squad of elite crossgobbos are sitting in your entrance hall this could cause problems.
Has anyone else observed this behaviour? And if so is it specific to goblins or consistent throughout other civilizations? (I noted that trolls brought by goblins behaved similarly though im not sure if trolls commanded by goblins would have goblin squad behaviour) It would be good to have confirmation from someone else that the design works. Suggestions for a name for this trap design are also welcome
(as are other personal trap designs)