l class="simple">
<li><p>r = a positive scalar whose value corresponds
to the upper (2r) and lower (r) corner points of the trapezoid.</p></li>
</ul>
</dd>
<dt>trapezoidal2:  </dt><dd><ul class="simple">
<li><p>r(1) = a value corresponding to the upper corner point of the trapezoid.</p></li>
<li><p>r(2) = a value corresponding to the lower corner point of the trapezoid.</p></li>
</ul>
</dd>
<dt>z_shaped:  </dt><dd><ul class="simple">
<li><p>r = a scalar whose value corresponds to the
upper (2r) and lower (r