ref: 022bc980b88ca6c06df2f4055ecc0b62231f01ea
dir: /sys/src/cmd/plot/libplot/poly.c/
#include "mplot.h" void plotpoly(int num[], double *ff[]){ double *xp, *yp, **fp; int i, *n; n = num; fp = ff; while((i = *n++)){ xp = *fp++; yp = xp+1; move(*xp, *yp); while(--i){ xp += 2; yp += 2; vec(*xp, *yp); } } }