diff --git a/scratch.md b/scratch.md
new file mode 100644
index 0000000..6b1db2d
--- /dev/null
+++ b/scratch.md
@@ -0,0 +1,44 @@
+# input
+
+1 2
+3 1
+
+# rules
+
+1u3 1d3 1r2 1l2 1u2 1d2 1l3 1r3
+3u1 3d1 3r1 3l1
+2u1 2d1 2r1 2l1
+
+# grid
+
++---+---+
+|123|123|
+|   |   |
++---+---+
+|123|123|
+|   |   |
++---+---+
+
+# cell 0x0
+
+1 u1 d1 l1 r1
+2 u1 d1 l1 r1
+3 u1 d1 l1 r1
+
+# cell 0x1
+
+1 u1 d1 l1 r1
+2 u1 d1 l1 r1
+3 u1 d1 l1 r1
+
+# cell 1x0
+
+1 u1 d1 l1 r1
+2 u1 d1 l1 r1
+3 u1 d1 l1 r1
+
+# cell 1x1
+
+1 u1 d1 l1 r1
+2 u1 d1 l1 r1
+3 u1 d1 l1 r1
diff --git a/src/Main.elm b/src/Main.elm
index b8cd49b..0a68af6 100644
--- a/src/Main.elm
+++ b/src/Main.elm
@@ -11,7 +11,7 @@ import Grid exposing (Grid)
 import Heap
 import Html as RootHtml
 import Html.Styled as Html exposing (Html)
-import Html.Styled.Attributes exposing (css, style)
+import Html.Styled.Attributes as Attributes exposing (css, style)
 import Html.Styled.Events as Events
 import Image exposing (Image)
 import Murmur3
@@ -233,7 +233,7 @@ view model =
                         average items =
                             List.sum items / toFloat (List.length items)
                     in
-                    Image.viewColor []
+                    Image.viewColor [ Attributes.attribute "data-count" (String.fromInt (Set.size indexes)) ]
                         (Color.fromRGBA
                             { red = average reds
                             , green = average greens
diff --git a/src/Wave.elm b/src/Wave.elm
index 9f85ada..4f34219 100644
--- a/src/Wave.elm
+++ b/src/Wave.elm
@@ -222,7 +222,11 @@ propagateInDirection source cell direction ( Wave wave, todo ) =
                                 wave.entropy
                     }
                 , -- TODO: add this as a target for propagation if it's not already in this list -
-                  todo
+                  if not (List.member target todo) then
+                    target :: todo
+
+                  else
+                    todo
                 )
 
 
diff --git a/template b/template
new file mode 100644
index 0000000..6b1db2d
--- /dev/null
+++ b/template
@@ -0,0 +1,44 @@
+# input
+
+1 2
+3 1
+
+# rules
+
+1u3 1d3 1r2 1l2 1u2 1d2 1l3 1r3
+3u1 3d1 3r1 3l1
+2u1 2d1 2r1 2l1
+
+# grid
+
++---+---+
+|123|123|
+|   |   |
++---+---+
+|123|123|
+|   |   |
++---+---+
+
+# cell 0x0
+
+1 u1 d1 l1 r1
+2 u1 d1 l1 r1
+3 u1 d1 l1 r1
+
+# cell 0x1
+
+1 u1 d1 l1 r1
+2 u1 d1 l1 r1
+3 u1 d1 l1 r1
+
+# cell 1x0
+
+1 u1 d1 l1 r1
+2 u1 d1 l1 r1
+3 u1 d1 l1 r1
+
+# cell 1x1
+
+1 u1 d1 l1 r1
+2 u1 d1 l1 r1
+3 u1 d1 l1 r1