Example 9.4.2

y1={ 0.000,  0.000,  0.000, 22.786, 42.130,  0.000, 12.921,
    12.921, 18.435,  26.565, 0.000,  0.000,  0.000,  0.000,
    18.435,  0.000,  0.000, 18.435, 18.435, 36.271,  0.000,
     0.000,  0.000, 12.921, 33.211};
y2={ 0.000, 18.435, 45.000, 53.729, 90.000, 12.921, 18.435,
    42.130, 56.789, 67.214,  0.000, 12.921, 22.786, 46.789,
    67.213,  0.000, 12.921, 42.130, 56.789, 77.079, 12.921,
     0.000, 39.231, 53.729, 67.213};
y3={30.000, 33.211, 60.000, 90.000, 90.000, 26.565, 33.211,
    77.079, 90.000, 90.000,  0.000, 22.786, 77.079, 77.079,
    90.000,  0.000, 22.786, 77.079, 90.000, 90.000, 26.565,
    22.786, 71.565, 90.000, 90.000};
y4={30.000, 33.211, 71.565, 90.000, 90.000, 26.565, 33.211,
    90.000, 90.000, 90.000,  0.000, 30.000, 77.079, 90.000,
    90.000, 12.921, 26.565, 77.079, 90.000, 90.000, 26.565,
    30.000, 90.000, 90.000, 90.000};
y5={30.000, 33.211, 71.565, 90.000, 90.000, 26.565, 33.211,
    90.000, 90.000, 90.000, 12.921, 33.211, 77.079, 90.000,
    90.000, 18.435, 30.000, 77.079, 90.000, 90.000, 26.565,
    30.000, 90.000, 90.000, 90.000};
x1={5.5984, 6.0161, 6.4134, 6.8459, 7.2793, 5.5984, 6.0161,
    6.4135, 6.8459, 7.2793, 5.5984, 6.0161, 6.4135, 6.8459,
    7.2793, 5.5984, 6.0161, 6.4135, 6.8459, 7.2793, 5.5984,
    6.0162, 6.4135, 6.8459, 7.2793};
x2={0.6695, 0.6405, 0.7290, 0.7700, 0.5655, 0.7820, 0.8120,
    0.8215, 0.8690, 0.8395, 0.8615, 0.9045, 1.0280, 1.0445,
    1.0455, 0.6195, 0.5305, 0.5970, 0.6385, 0.6645, 0.5685,
    0.6040, 0.6325, 0.6845, 0.7230};