Making those diagrams in Mathematica would be extraordinary painful. It's probably something similar to that (a custom XKCD-like style) but for a dedicated diag

Making those diagrams in Mathematica would be extraordinary painful. It's probably something similar to that (a custom XKCD-like style) but for a dedicated diagramming tool. I don't know of any tool with such a style though, so I'm guessing it's custom.