()
{
  cls(0);
  setcol(0xffffff);
  srand(1234);
  for(i=0; i<1000; i++) {
   rad = int( abs(nrnd*10) );
   x=rnd*xres;
   y=rnd*yres;
   drawcircle(x,y,rad);
   //drawsph(x,y,-rad);
  }
}

drawcircle(cx,cy,r) {
  if (cx+r < 0 || cy+r < 0) return;
  if (cx-r > xres || cy-r > yres) return;
  r = int(r);
  if (r<=0) return;
  r2 = r+r;
  x = r; y = 0;
  dy = -2; dx = r2+r2 - 4;
  d = r2-1;
  while(y<=x) {
    setpix(cx-x, cy-y);
    setpix(cx+x, cy-y);
    setpix(cx-x, cy+y);
    setpix(cx+x, cy+y);
    setpix(cx-y, cy-x);
    setpix(cx+y, cy-x);
    setpix(cx-y, cy+x);
    setpix(cx+y, cy+x);
    d += dy;
    dy -= 4;
    ++y;
    if (d<0) {
      d += dx;
      dx -= 4;
      --x;
    }
  }
}