Animate it ;-)

#!/usr/bin/perl
use Term::Cap;
$t= Tgetent Term::Cap;
$t=$t->Tgoto('cm', 0, 0);
for$i(1..shift){
  print $t;
  map{
    $a=1-$_/10;
    map{
      $d=$a;
      $e=$b=$_/20-2;
      map{
        ($d,$e)=(2*$d*$e+$a,$e**2-$d**2+$b);
        $c=$d**2+$e**2>4?_:0
      }1..$i;
      print$c
    }0..59;
    print$/
  }0..20;
}
[download]

Try perl mandel.pl 13. If I pass 99, there'll be a block of zeroes at the end.

<update>

It's not an overflow issue. As the area delimiting the mandelbrot converges to a line with increased iterations over the inner loop, there's not enough resolution to draw it. You can skip the outer area exiting the inner loop as soon as $d**2+$e**2>4

map{
  $a=1-$_/10;
  map{
    $d=$a;
    $e=$b=$_/20-2;
    for(1..99){
      ($d,$e)=(2*$d*$e+$a,$e**2-$d**2+$b);
      $c=$d**2+$e**2>4?_:0;
      last if $c eq _
    }
    print$c
  }0..59;
  print$/
}0..20;
[download]

I wonder how that works on your windows box, though.

</update>

--shmem

_($_=" "x(1<<5)."?\n".q·/)Oo.  G°\        /
                              /\_¯/(q    /
----------------------------  \__(m.====·.(_("always off the crowd"))."·
");sub _{s./.($e="'Itrs `mnsgdq Gdbj O`qkdq")=~y/"-y/#-z/;$e.e && print}