On 26 February 2013 19:20, nobu (Nobuyoshi Nakada) <nobu / ruby-lang.org>wrot=
e:

>
> Why is it called as =F4, half of =F0?
>

It's actually two of =F0.  The reason for the name is justified here:
http://tauday.com/tau-manifesto#sec:one_turn

In summary: tau is the first letter of the Greek word "tornos" (lathe),
which is the root of the English word "turn;" and the tau constant (2*PI)
is the ratio of a circle's radius to its circumference (i.e. one _turn_.)
Also "the horizontal line in each letter suggests that we interpret the
"legs" as _*denominators_*, so that =F0 has two legs in its denominator,
while =F4 has only one. Seen this way, the relationship =F4=3D2=F0 is perfe=
ctly
natural."

--=20
  Matthew Kerwin, B.Sc (CompSci) (Hons)
  http://matthew.kerwin.net.au/
  ABN: 59-013-727-651

  "You'll never find a programming language that frees
  you from the burden of clarifying your ideas." - xkcd