public override string ToString()
{
return(String.Format("[{0}, {1}, {2}, {3}]\n[{4}, {5}, {6}, {7}]\n[{8}, {9}, {10}, {11}]\n[{12}, {13}, {14}, {15}]",
F11.ToString("r"), F12.ToString("r"), F13.ToString("r"), F14.ToString("r"),
F21.ToString("r"), F22.ToString("r"), F23.ToString("r"), F24.ToString("r"),
F31.ToString("r"), F32.ToString("r"), F33.ToString("r"), F34.ToString("r"),
F41.ToString("r"), F42.ToString("r"), F43.ToString("r"), F44.ToString("r")));
}
