2014-12-02: make H easier to read by reducing the use of curly infix.

make H easier to read by reducing the use of curly infix.

diff --git a/examples/ensemble-estimation.w b/examples/ensemble-estimation.w
--- a/examples/ensemble-estimation.w
+++ b/examples/ensemble-estimation.w
@@ -97,7 +97,10 @@ x are parameters to be optimized, pos is
                       *
                          list-ref x i
                          expt pos 2
-                         exp : - {{{pos - (list-ref x-pos i)} expt 2} / ystretch}
+                         exp 
+                           - 
+                             / : expt {pos - (list-ref x-pos i)} 2
+                               . ystretch
 
 
 ;; We start with true observations which we will disturb later to get