My friends had started to mutter among themselves. Deciding it was best to get back on track, I continued, "back to Occlumency, your eyes are also the only entrance into your mind. That means there is only one way in. You can build your defense to use that to your advantage. Several examples," I waved over the tables I had the room bring out. "Include castle walls, mazes, puzzles. The more complex, the harder it would be for them to break through."