This sin't a log scale nor powers of two... I don't know why you're thinking this...

Real Interest Rate = Nominal Rate - Inflation

The line (green vs. blue) is just a Y=X where Real Interest Rate =0

I'm not sure if you're trolling, or just don't know economics.

Edit: Oh! You mean the scale! Yeah, that doesn't matter from an economics perspective. You just need to look at the percentages. It's to force the 45 Degree line that separates positive real rates from negative real rates.