code: function gaussRandom() {
    if (gaussRandom.returnV) {
      gaussRandom.returnV = false;
      return gaussRandom.vVal;
    }
    var u = 2 * Math.random() - 1;
    var v = 2 * Math.random() - 1;
    var r = u * u + v * v;
    if (r == 0 || r > 1) {
      return gaussRandom();
    }
    var c = Math.sqrt(-2 * Math.log(r) / r);
    gaussRandom.vVal = v * c; // cache this
    gaussRandom.returnV = true;
    return u * c;
  }
docs: Random numbers utils