Index: detour/3_hull.html
===================================================================
--- detour/3_hull.html	(revision 953)
+++ detour/3_hull.html	(revision 954)
@@ -21,7 +21,7 @@
 <p>
 There are 8 different ways a this can be done, depending on how existing
 objects are arranged in the current state of the board. The first choice is
-made by the caller: switch layer or stay on layer; this is made by the caller.
+made by the caller: switch layer or stay on layer.
 <p>
 
 <div class="img"><center>