Consider adding an example with "linear" x-axis

[twitwi]

I found this library quite simple to use. As a new user, the surprising thing came from the (default) "band" x-axis setup. At first I thought it was a design constraint (and almost switched to some other lib) but I realized we can configure the x-axis as "linear" and now everything is fine :)

An example with a linear x-axis might avoid people like me from wrongly thinking it is not possible.