<script src="http://spelprogrammering.nu/simple.js">
function start()
{
  turtle.x = 2;
  turtle.y = 2;
  shape = 'a';
  rules = {'F': 'F',
           'a': '-bF+aFa+Fb-',
           'b': '+aF-bFb-Fa+',
           '+': '+',
           '-': '-'};

  events = {};
  events['F'] = function() { turtle.move(6); };
  events['a'] = function(){};
  events['b'] = function(){};
  events['+'] = function() { turtle.turnLeft(angle); };
  events['-'] = function() { turtle.turnRight(angle) };

  angle = 90;

  iterations = 7;

  for (var i = 0; i < iterations; i++)
  {
    currentLength = shape.length;
    newShape = '';
    for (var u = 0; u < currentLength; u++)
      newShape += rules[shape.charAt(u)];
    shape = newShape;
  }

  for (var i = 0; i < shape.length; i++)
    events[shape.charAt(i)]();
}
</script>