x1 = [1     2   5   6   7   8  10  13  17];        % Curve 1
y1 = [3.0 3.7 3.9 4.2 5.7 6.6 7.1 6.7 4.5];
dy1= [1.0  -0.67];
x2 = [17   20  23  24  25  27  27.7];              % Curve 2
y2 = [4.5 7.0 6.1 5.6 5.8 5.2 4.1];
dy2= [2.0  -4.0];
x3 = [27.7 28  29  30];                            % Curve 3
y3 = [ 4.1  4.3 4.1 3.0];
dy3= [ 0.33 -1.5];
