From ee059bc60c6e21077739279a7b8dd0aa28c74e76 Mon Sep 17 00:00:00 2001
From: Simon Tatham <anakin@pobox.com>
Date: Fri, 10 Jun 2005 11:34:02 +0000
Subject: [PATCH] Disable shuffle overlap checking in the special case w=h=n.

[originally from svn r5940]
---
 twiddle.c | 9 ++++++++-
 1 file changed, 8 insertions(+), 1 deletion(-)

diff --git a/twiddle.c b/twiddle.c
index 8388f47..58b4cb5 100644
--- a/twiddle.c
+++ b/twiddle.c
@@ -363,7 +363,14 @@ static char *new_game_desc(game_params *params, random_state *rs,
                  */
                 oldtotal = prevmoves[y*rw+x];
                 newtotal = oldtotal + r;
-            } while (abs(newtotal) < abs(oldtotal) || abs(newtotal) > 2);
+                
+                /*
+                 * Special case here for w==h==n, in which case
+                 * there is actually no way to _avoid_ all moves
+                 * repeating or undoing previous ones.
+                 */
+            } while ((w != n || h != n) &&
+                     (abs(newtotal) < abs(oldtotal) || abs(newtotal) > 2));
 
             do_rotate(grid, w, h, n, params->orientable, x, y, r);