bt.margin</code>: Margins of the plot as used by
      <code>par("mar")</code>. The default is <code>c(0.5, 1, 0, 0)</code>.</p></li>
<li><p><code>bt.color_surface</code>: Color of the surface of the
      perspective plot. The default is <code>"lightgrey"</code>.</p></li>
<li><p><code>bt.color_branches</code>: Color used for the branches of the
      barrier tree. Per default there will be one color per level.</p></li>
<li><p><code>bt.persp_border</code>: Color of the lines / borders around
      each face