 curves, for each value of <code>.width</code> (note that <code>k</code>
and <code>.width</code> are not necessarily the same). This is in contrast to most functional boxplot
or curve boxplot approaches, which tend to simply take the <code>.width</code>% deepest curves, and
are generally quite conservative (i.e. they may contain more than <code>.width</code>% of the curves).</p>
<p>See Mirzargar <em>et al.</em> (2014) or Juul <em>et al.</em> (2020) for an accessible introduction
to data depth and curve boxp