Generally, Pythagorean tuning uses perfect fifths, as it's the easiest to hear and to match using harmonics. That example is just showing that if you using cons

Generally, Pythagorean tuning uses perfect fifths, as it's the easiest to hear and to match using harmonics. That example is just showing that if you using consecutive intervals (such as fifths) then other intervals (such as octaves and thirds) won't line up.