of two triangles separated by a diagonal. So it can be calculated only
for elements consisting of 4 nodes.
-\image html image25.png
+ <b><center>JA=0.25 * (A1 + A2 + A3 + A4)
+ <br> TAPER= MAX(|A1/JA - 1|, |A2/JA - 1|, |A3/JA - 1|, |A4/JA - 1|)</center></b>
<br><em>To apply the Taper quality criterion to your mesh:</em>