1 files changed, 6 insertions, 0 deletions
diff --git a/field.h b/field.h
index 728d75a..7bce8c5 100644
--- a/field.h
+++ b/field.h
@@ -16,6 +16,12 @@ enum intersection_type {
     one_path     = '1',
     two_paths    = '2',
     three_paths  = '3',
+    /*
+     * Yellow blocks': ghosts can't go up from these tiles during normal
+     * movement. When entering from left or right, they can only continue
+     * straight. This restriction is ignored in frightened mode or during
+     * mode transitions.
+     */
     yellow_block = 'y',
     direct_path
 };