Fix a typo in the Black Box docs examples.

A letter offset by one from a ball on the edge should be an R, not an
H. Thanks to Kevin Buzzard for pointing out the error.

diff --git a/puzzles.but b/puzzles.but
index 6b39630a93eeaf822a34a46e058b5c880bd181c0..dfb58030837cbe9cc3f6ce666a11954c2149dd2b 100644 (file)
--- a/puzzles.but
+++ b/puzzles.but
@@ -1585,7 +1585,7 @@ of the beam behaviours shown above:
 \c |......O.|
 \c H........|
 \c |.....O..|
-\c  12-RH---
+\c  12-RR---
 
 As shown, it is possible for a beam to receive multiple reflections
 before re-emerging (see turn 3). Similarly, a beam may be reflected