Misuse of "y" & "z" terms
Thanks for pointing me to the link, and, as a long-time peruser of bj21, I am familiar (sadly) with the whole Norm W saga.
Unfortunately, the explanation for the scatterplot provided is wrong in that Norm has flip-flopped the "z" and "y" axes (only in the description, not in the graph itself).
At any rate, I see now that, acc'ing to the description, the z-axis (with a scale from 1-8) represents "ease of use."
Interesting to note that the 'best' system would appear (as Norm writes in his description) in the top, right, back 'corner' of the graph--which is conspicuously empty.