I'll add that it's also great documentation / example material for how to use CircuitLab. In fact, that's how it started.

In many ways, circuit simulators are a power user tool, and so I started this project by just making a larger library of example circuits. It then became clear that I needed to put the circuits together in context, and the idea for the textbook popped up since the context many of our customers share (at least the hobbyist and education segments) is in learning electronics.

Now, I'm inspired by communicating in this part-theory, part-practical style that seems hard to find in conventional resources.