(1) Take a semicircle of radius pi.
(2) The diameter is two pi and the semi-circumference is pi.
(3) The semi-circumference is an inflation of the diameter which is two pi, also known as Tau.
(4) Obviously, the semi-circumference is greater than the diameter.
(5) Pi's numerical value is greater than tau in circles with radius pi.
Spock comes along and picks one of the steps above that is illogical. Which is it?