private void calculatePercentages() {
        metalPercentages = new double[3];
        double point1, point2, larger, smaller;
        point1 = Math.random();
        point2 = Math.random();
        if (point1 < point2) {
            larger = point2;
            smaller = point1;
        } else {
            larger = point1;
            smaller = point2;
        }
        metalPercentages[0] = smaller;
        metalPercentages[1] = larger - smaller;
        metalPercentages[2] = 1.00 - larger;
    }