diff --git a/jsssnake/simplesnake.html b/jsssnake/simplesnake.html
index c97cd28..eb713f7 100644
--- a/jsssnake/simplesnake.html
+++ b/jsssnake/simplesnake.html
@@ -94,7 +94,7 @@ var Snake = {
 				var next = 
 					direction == 'n' ? (i < w ? l - w + i : i - w)
 					// XXX BUG: this returns 256 when at x = 0...
-					: direction == 's' ? (i > (l-w) ? i - (l-w) : i + w)
+					: direction == 's' ? (i > (l-w-1) ? i - (l-w) : i + w)
 					: direction == 'e' ? ((i+1)%w == 0 ? i - (w-1) : i + 1)
 					: direction == 'w' ? (i%w == 0 ? i + (w-1) : i - 1)
 					: null