I am a firm believer that people learn something important when they try to do something they are not good at. I have recently bought a Theremin, and I want to pretend that I am anything but not good at playing it, but, like, it is hard to master:

I noticed that a Theremin has a distinctive shape: an upright antenna that you use to control pitch (the high-lowness of a note), and a horizontal antenna loop you use to control volume. To my (not so great) surprise, I discovered that no one had yet done an origami model for this thing, so set about having a go.

I started with the fish base, long flap for the pitch antenna, long flap for the stand, then 2 shorter flaps become the volume loop. Some accordion pleating and the basic morphology is there. You can (I hope) see the development in the sequence below:

It is a start, I might try to refine it (add knobs, refine the antennae, etc). Happy with v1.