);
    goog.vec.Matrix4.add(m0, m1, m2);
    assertElementsEquals(
        [1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16], m0);
    assertElementsEquals(
        [9, 10, 11, 12, 13, 14, 15, 16, 1, 2, 3, 4, 5, 6, 7, 8], m1);
    assertElementsEquals(
        [10, 12, 14, 16, 18, 20, 22, 24, 10, 12, 14, 16, 18, 20, 22, 24], m2);

    goog.vec.Matrix4.add(m0, m1, m0);
    assertElementsEquals(
        [9, 10, 11, 12, 13, 14, 15, 16, 1, 2, 3, 4, 5, 6, 7, 8], m1);
    assertElementsEquals(
        [10, 