diff --git a/puzzles.but b/puzzles.but
index 523574c..2508fe3 100644
--- a/puzzles.but
+++ b/puzzles.but
@@ -1553,11 +1553,11 @@ affected by balls in one of the following ways:
    re-emerge. This includes beams that meet a ball on the first rank
    of the arena.
 
-\b A beam with a ball to its front-left square gets deflected 90 degrees
-   to the right.
+\b A beam with a ball in its front-left square and no ball ahead of it
+   gets deflected 90 degrees to the right.
 
-\b A beam with a ball to its front-right square gets similarly deflected 
-   to the left. 
+\b A beam with a ball in its front-right square and no ball ahead of
+   it gets similarly deflected to the left.
 
 \b A beam that would re-emerge from its entry location is considered to be
    \q{reflected}.