// The radial island radius is based on overlapping sine waves
  static public var ISLAND_FACTOR:Number = 1.07;  // 1.0 means no small islands; 2.0 leads to a lot
  static public function makeRadial(seed:int):Function {
    var islandRandom:PM_PRNG = new PM_PRNG();
    islandRandom.seed = seed;
    var bumps:int = islandRandom.nextIntRange(1, 6);
    var startAngle:Number = islandRandom.nextDoubleRange(0, 2*Math.PI);
    var dipAngle:Number = islandRandom.nextDoubleRange(0, 2*Math.PI);
    var dipWidth:Number = islandRandom.nextDoubleRange(0.2, 0.7);

    function inside(q:Point):Boolean {
      var angle:Number = Math.atan2(q.y, q.x);
      var length:Number = 0.5 * (Math.max(Math.abs(q.x), Math.abs(q.y)) + q.length);

      var r1:Number = 0.5 + 0.40*Math.sin(startAngle + bumps*angle + Math.cos((bumps+3)*angle));
      var r2:Number = 0.7 - 0.20*Math.sin(startAngle + bumps*angle - Math.sin((bumps+2)*angle));
      if (Math.abs(angle - dipAngle) < dipWidth
          || Math.abs(angle - dipAngle + 2*Math.PI) < dipWidth
          || Math.abs(angle - dipAngle - 2*Math.PI) < dipWidth) {
        r1 = r2 = 0.2;
      }
      return  (length < r1 || (length > r1*ISLAND_FACTOR && length < r2));
    }

    return inside;
  }