It would help to have the data.
x = linspace(0, 110).'; % Entire Code Assumes Column Vectors
y1 = randn(size(x))/100 + 0.1;
y1d = 0.01*[-1 1] + y1;
y2 = randn(size(x))/100 + 0.01;
y2d = 0.01*[-1 1] + y2;
figure
plot(x, y1, '-b')
hold on
plot(x, y2, '-r')
patch([x; flip(x)], [y1d(:,1); flip(y1d(:,2))], 'b', 'EdgeColor','b', 'LineStyle','--', 'FaceAlpha',0.25)
patch([x; flip(x)], [y2d(:,1); flip(y2d(:,2))], 'r', 'EdgeColor','r', 'LineStyle','--', 'FaceAlpha',0.25)
hold off
Make appropriate changes to get the result you want.
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