JSFiddle - React, Tailwind, and code Playground

HTML

<html>
<head>
<title>The Mandelbro™</title>
</head>
<body>
<div id="out"></div>
Check out this <a href="https://gist.github.com/1261166">gist</a> for details.
</body>
</html>

CSS

#out {
  font-size: 10px;
  line-height: 3px;
  width: 300px;
  word-wrap:break-word; /* Force line break after 300px */
  font-family: "Arial Black", Helvetica, Verdana;
}
font {
  display: inline-block;
  width: 1px;
  height: 1px;
}

JavaScript

var mandelbrot =
function(s,r,i,k,n){for(n=9e4;n--;s[n]='█'.fontcolor((k&63)*4+1e5))for(r=i=k=0;r*r+i*i+k++<63;i=t)t=2*r*i+1-n/45e3,r=r*r-i*i+1-n/100%3}

var a = [];
mandelbrot(a);
document.getElementById('out').innerHTML = a.join('');