User blog comment:Mrob27/The moat experiment/@comment-4829477-20120210141606/@comment-4728735-20120210224700

Also, if you box in a superblock or two then make a bunch of passive traps, you can then connect the traps with corridors and push the astronauts down them, leading them to a big central holding pen. The astronauts may also find their way down the corridors on their own.