Change the size of a fill sample in Matlab legend
I'm creating a plot in matlab that includes some lines, as well as a fill.  For example, 

    fill([0 1 1], [0 1 0], [.9 .9 .9]);
    plot(rand(5, 1), 'b');
    plot(rand(5, 1), 'r');
    plot(rand(5, 1), 'g');
    legend('fill', 'line one', 'line two', 'line three');

I can change the length of the sample lines in the legend with: 
    
    f = findobj('type', 'line')
    set(f(2), 'XData', [.2, .3]) % Changes line three
    set(f(4), 'XData', [.2, .3]) % Changes line two
    set(f(6), 'XData', [.2, .3]) % Changes line one

But this method doesn't seem to work for the fill. How do I change the size of the fill sample in the legend?
Change the size of a fill sample in Matlab legend
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I'm creating a plot in matlab that includes some lines, as well as a fill.  For example, 

    fill([0 1 1], [0 1 0], [.9 .9 .9]);
    plot(rand(5, 1), 'b');
    plot(rand(5, 1), 'r');
    plot(rand(5, 1), 'g');
    legend('fill', 'line one', 'line two', 'line three');

I can change the length of the sample lines in the legend with: 
    
    f = findobj('type', 'line')
    set(f(2), 'XData', [.2, .3]) % Changes line three
    set(f(4), 'XData', [.2, .3]) % Changes line two
    set(f(6), 'XData', [.2, .3]) % Changes line one

But this method doesn't seem to work for the fill. How do I change the size of the fill sample in the legend?