macro which produces the symbol 
was created by Richard Palais. The reasons for its creation are described in
The following
macro which produces the symbol
was created by Richard Palais. The reasons for its creation are described in
"Pi
is wrong!" by Bob Palais, in The Mathematical Intelligencer, Springer-Verlag
New York Summer 2001, vol. 23, no. 3., pp. 7-8.
\def \newpi{{\pi\mskip -7.8 mu \pi}}