width = 80;
lx=-1;
loop(1000000,
  x = ((1+sin(pos))*0.5 * width)|0;
  lx >= -1 && lx!=x ? (
    loop(min(x,lx), printf(" "));
    loop(abs(x-lx), printf("*"));
    loop(width-max(x,lx), printf(" "));
  ) : (
    loop(x, printf(" "));
    printf("*");
    loop(width-1-x, printf(" "));
  );
  lx=x;
  printf("\n");
  pos += 0.25 + sin(pos*0.32)*0.2;
);