Triangle pot???

How about....

A Pyramid pot??? You put your bait in the bottom(detachable) and the top has an opening. Here's how it works, the shrimp smell the good stuff and then it's an all out race for the king of the pyramid. Unfortunately the first king and all successors end up in the trap! \:D

...as for placement of lines, that will have to be figured out somehow unless you have strong telekenetic powers and are able to use your mind to pull up the pot. ;\)