From 99ebedc06c02a512beaf15b7cfa48368df432fd4 Mon Sep 17 00:00:00 2001
From: Brian Hicks <brian@brianthicks.com>
Date: Fri, 10 Jan 2020 11:32:40 -0500
Subject: [PATCH] use union instead of intersect for possible tiles

---
 src/Wave.elm | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/Wave.elm b/src/Wave.elm
index 3a382c4..5e7255f 100644
--- a/src/Wave.elm
+++ b/src/Wave.elm
@@ -203,7 +203,7 @@ propagateInDirection source cell direction ( Wave wave, todo ) =
                             remaining_
                                 |> Set.toList
                                 |> List.filterMap (\value -> Dict.get ( value, direction ) wave.rules)
-                                |> List.foldl Set.intersect Set.empty
+                                |> List.foldl Set.union Set.empty
 
                 reduced =
                     Set.intersect remaining possibleInDirection