/* From OpenXM: OpenXM/src/asir-contrib/packages/src/ccurve.rr,v 1.1 2004/03/11 12:25:20 takayama Exp  */
/* From asir-book/Prog/ccurve */
import("glib")$
def cCurve(P) {
  if (length(P) < 2) return(0);
  A = P[0][0];
  B = P[0][1];
  C = P[1][0];
  D = P[1][1];
  Tmp = [[A,B],[(A+D+C-B)/2,(B+A+D-C)/2],
         [(A+D+C-B)/2,(B+A+D-C)/2],[C,D]];
  return(append2(Tmp,cCurve(cdr(cdr(P)))));
}
def append2(A,B) {
  if (type(B) == 0) return A;
  else return append(A,B);
}
def ccurve(N) {
   Tmp = [[0,0],[1,0]];
   for (I=0; I<N; I++) {
      Tmp = cCurve(Tmp);
      print(Tmp);
   }
   glib_window(-1,-1,2,0.5);
   for (I=0; I<length(Tmp)-1; I++) {
     glib_line(Tmp[I][0],Tmp[I][1],Tmp[I+1][0],Tmp[I+1][1]); glib_flush();
   }
}
ccurve(6); glib_flush();
"Type in, for example,  ccurve(8);";