We have a magic white board that can print out a big piece of paper showing everything on it. We also take pictures of it (and lesser white boards) to record designs agreed. Those pictures generally get put into a formal design document that is reviewed, signed, approved and all the rest of it.

Explanations work better without lengthy pauses. Ideally, I can explain the thing without stopping too long.

> Why don't you use documentation?

I do if it's necessary. Sometimes it's not necessary.

> Oh, and how do you version control the white board?

I don't.

My original comment was mostly meant as snark, but I've had an interviewer take photos during a whiteboard exercise for this reason.

The resulting svg or png can be then added to the docs folder of a project. Works well with sphinx, etc.