Please read the manual for more cool pies ;)
\pie{10/A, 20/B, 30/C, 40/D}
\pie[polar]{10/A, 20/B, 30/C, 40/D}
\pie[square]{40/A, 30/B, 20/C, 10/D}
\pie[cloud, text=inside, scale font]{10/A, 20/B, 30/C, 40/D}