Twoscales example

John, I think it would be a good Idea to beef up the two

    > scales example by adding a second plot were the y axes
    > were independent while the x axis is shared. This is a
    > more common use of two scales.

Now you've confused me. In, the x axis *is shared* and
there are two independent y axes. I agree that this is the common use
case for multiple scales on the same axes, but that is what two_scales
already does.

Do you mean something like examples/ by chance?