Designing a "Trick"

I finally have the ideas for Chapter Two of Hemlock and the Dangerous Depths ready. I have written a portion of it, but it's not completed yet. The beginning of this novel is (necessarily) setting the stage for new adventures. Much like Hemlock, I am anxious to begin (writing) those adventures. But there are smaller excitements to be had before the major arc begins.

One of the new plot developments requires designing a "trick". A trick, in the context of a fun house, is something that the visitor experiences in a room that is amusing, frightening, etc. When I use the term "trick", I mean something mysterious in the story that requires a cognitive exercise (rather than a conversation or a fight) to figure out. Tricks are a fun part of any fantasy tale.

The problem with tricks is that they are hard to come up with. You rarely can just make up something off the cuff. Because it is a cognitive challenge, it has to be credible, fresh, and compatible with the setting of the story. It took me a while to come up with a new trick, but I finally did, and I'm happy with it. As is often the case, it was inspired by music.