Index: detour/3_hull.html
===================================================================
--- detour/3_hull.html	(revision 894)
+++ detour/3_hull.html	(revision 895)
@@ -175,6 +175,14 @@
 	<li> always add both endponits of the offending N1 line
 </ul>
 <p>
+
+<div class="img"><center>
+<p><img src="img/geo_wallin.png">
+<p>Figure 3/6. a. N1 inside N3, crossing edges; b. spokes and convex hull;
+c. path chosen; d. same case but no crossing; e. spokes and convex hull;
+f. path chosen;
+</center></div>
+<p>
 Once those corners are collected, the path calculation is:
 <ul>
 	<li> calculate a new convex hull using the above corners and their N3-N1 spokes