le2bnd(..., 'prc', prc)| specifies the percentile values
% corresponding to lower and upper bounds.  These should come in pairs,
% from lowest to highest percentile.  The default is [0 100].
%
% |ensemble2bnd(..., 'alpha', true)| indicates that boundedline patches
% should be plotted using tranparent patches rather than opaque patches.
%
% |ensemble2bnd(..., 'tlim', tlim)| changes the color limits associated
% with the patches or errorbars associated with percentiles. By default,
% the center lines/bars/poi