diff --git a/dotscape.mlb b/dotscape.mlb
index 716e76a..292199a 100644
--- a/dotscape.mlb
+++ b/dotscape.mlb
@@ -38,6 +38,7 @@ message-types/file-msg.sml
 message-types/input-msg.sml
 message-types/update-msg.sml
 
+fcore/file-string.sml
 fcore/quad-tree.sml
 
 fcore/common-update.sml
diff --git a/dsc b/dsc
index d536d5d..d437c89 100755
Binary files a/dsc and b/dsc differ
diff --git a/fcore/common-update.sml b/fcore/common-update.sml
index 98f6ec5..266b495 100644
--- a/fcore/common-update.sml
+++ b/fcore/common-update.sml
@@ -48,34 +48,37 @@ struct
 
   fun getSaveSquaresMsg (model: app_type) =
     let
-      val {layerTree, canvasWidth, canvasHeight, ...} = model
-      val str =
+      val {layerTree, canvasWidth, canvasHeight, openFilePath, ...} = model
+      val saveString =
         CollisionTree.toSaveString (layerTree, canvasWidth, canvasHeight)
-      val msg = SAVE_SQUARES str
+      val msg = SAVE_SQUARES {output = saveString, filepath = openFilePath}
     in
       (model, [FILE msg])
     end
 
-  fun getLoadSquaresMsg model =
-    (model, [FILE LOAD_SQUARES])
+  fun getLoadSquaresMsg (model: app_type) =
+    let val msg = LOAD_SQUARES {filepath = #openFilePath model}
+    in (model, [FILE msg])
+    end
 
   fun getExportSquaresMsg (model: app_type) =
     let
-      val {layerTree, canvasWidth, canvasHeight, ...} = model
+      val {layerTree, canvasWidth, canvasHeight, openFilePath, ...} = model
 
       val maxSide = Int.max (canvasWidth, canvasHeight)
       val squares = LayerTree.flatten (maxSide, layerTree)
 
       val exportString =
         CollisionTree.toExportString (squares, canvasWidth, canvasHeight)
-      val msg = EXPORT_SQUARES exportString
+      val msg = EXPORT_SQUARES {output = exportString, filepath = openFilePath}
     in
       (model, [FILE msg])
     end
 
   fun getCollisionMsg (model: app_type) =
     let
-      val {layerTree, canvasWidth, canvasHeight, modalNum, ...} = model
+      val {layerTree, canvasWidth, canvasHeight, modalNum, openFilePath, ...} =
+        model
 
       val maxSide = Int.max (canvasWidth, canvasHeight)
       val squares = LayerTree.flatten (maxSide, layerTree)
@@ -83,7 +86,10 @@ struct
       val exportString =
         CollisionTree.toCollisionString
           (squares, canvasWidth, canvasHeight, modalNum)
-      val msg = EXPORT_COLLISIONS exportString
+
+      val exportFilePath = FileString.getCollisionFilename openFilePath
+      val msg =
+        EXPORT_COLLISIONS {output = exportString, filepath = exportFilePath}
 
       val model = AppWith.modalNum (model, 0)
     in
diff --git a/fcore/file-string.sml b/fcore/file-string.sml
new file mode 100644
index 0000000..f4b3d06
--- /dev/null
+++ b/fcore/file-string.sml
@@ -0,0 +1,59 @@
+structure FileString =
+struct
+  fun findLastChr (str, pos, findChr) =
+    if pos < 0 then ~1
+    else if String.sub (str, pos) = findChr then pos
+    else findLastChr (str, pos - 1, findChr)
+
+  fun extractFileName str =
+    let
+      val lastSlash = findLastChr (str, String.size str - 1, #"/")
+      val strStart = lastSlash + 1
+    in
+      if lastSlash = ~1 then str
+      else String.substring (str, strStart, String.size str - strStart)
+    end
+
+  fun removeFileExtension str =
+    let val lastDot = findLastChr (str, String.size str - 1, #".")
+    in if lastDot = ~1 then str else String.substring (str, 0, lastDot)
+    end
+
+  local
+    fun finish acc =
+      let val acc = List.rev acc
+      in String.implode acc
+      end
+
+    (* convert from kebab-case or snake_case to PascalCase *)
+    fun loop (#"-" :: chr :: tl, acc) =
+          let val acc = Char.toUpper chr :: acc
+          in loop (tl, acc)
+          end
+      | loop (#"_" :: chr :: tl, acc) =
+          let val acc = Char.toUpper chr :: acc
+          in loop (tl, acc)
+          end
+      | loop ([#"-"], acc) = finish acc
+      | loop ([#"_"], acc) = finish acc
+      | loop (chr :: tl, acc) =
+          loop (tl, chr :: acc)
+      | loop ([], acc) = finish acc
+  in
+    fun filenameToStructureName str =
+      let
+        val str = removeFileExtension str
+        val str = extractFileName str
+      in
+        (* capitalise first character in string *)
+        case String.explode str of
+          chr :: tl => let val chr = Char.toUpper chr in loop (tl, [chr]) end
+        | [] => ""
+      end
+  end
+
+  fun getCollisionFilename str =
+    let val str = removeFileExtension str
+    in str ^ "-collisions.sml"
+    end
+end
diff --git a/fcore/quad-tree.sml b/fcore/quad-tree.sml
index 30717ce..d36ef1b 100644
--- a/fcore/quad-tree.sml
+++ b/fcore/quad-tree.sml
@@ -1,57 +1,5 @@
 structure CollisionTree =
 struct
-  fun findLastChr (str, pos, findChr) =
-    if pos < 0 then ~1
-    else if String.sub (str, pos) = findChr then pos
-    else findLastChr (str, pos - 1, findChr)
-
-  fun extractFileName str =
-    let
-      val lastSlash = findLastChr (str, String.size str - 1, #"/")
-      val strStart = lastSlash + 1
-    in
-      if lastSlash = ~1 then str
-      else String.substring (str, strStart, String.size str - strStart)
-    end
-
-  local
-    fun removeFileExtension str =
-      let val lastDot = findLastChr (str, String.size str - 1, #".")
-      in if lastDot = ~1 then str else String.substring (str, 0, lastDot)
-      end
-
-    fun finish acc =
-      let val acc = List.rev acc
-      in String.implode acc
-      end
-
-    (* convert from kebab-case or snake_case to PascalCase *)
-    fun loop (#"-" :: chr :: tl, acc) =
-          let val acc = Char.toUpper chr :: acc
-          in loop (tl, acc)
-          end
-      | loop (#"_" :: chr :: tl, acc) =
-          let val acc = Char.toUpper chr :: acc
-          in loop (tl, acc)
-          end
-      | loop ([#"-"], acc) = finish acc
-      | loop ([#"_"], acc) = finish acc
-      | loop (chr :: tl, acc) =
-          loop (tl, chr :: acc)
-      | loop ([], acc) = finish acc
-  in
-    fun filenameToStructureName str =
-      let
-        val str = removeFileExtension str
-        val str = extractFileName str
-      in
-        (* capitalise first character in string *)
-        case String.explode str of
-          chr :: tl => let val chr = Char.toUpper chr in loop (tl, [chr]) end
-        | [] => ""
-      end
-  end
-
   structure BinTree =
   struct
     datatype 'a bintree =
diff --git a/green.dsc b/green.dsc
index e16fbe2..103ed82 100644
--- a/green.dsc
+++ b/green.dsc
@@ -1,3 +1,3 @@
 28 32 { 
-  [  { 0 25 0 26 0 0 0 1 }  { 1 7 1 9 0 0 0 1 }  { 1 24 5 24 0 0 0 1 }  { 1 25 3 25 184 216 248 1 }  { 1 26 1 26 120 152 232 1 }  { 1 27 5 27 0 0 0 1 }  { 2 6 2 6 0 0 0 1 }  { 2 7 2 7 184 216 248 1 }  { 2 8 2 8 240 248 248 1 }  { 2 9 4 9 184 216 248 1 }  { 2 10 2 10 0 0 0 1 }  { 2 25 2 26 184 216 248 1 }  { 3 5 6 5 0 0 0 1 }  { 3 6 3 6 184 216 248 1 }  { 3 7 3 7 240 248 248 1 }  { 3 8 3 10 184 216 248 1 }  { 3 8 4 9 184 216 248 1 }  { 3 11 3 16 0 0 0 1 }  { 3 11 5 11 0 0 0 1 }  { 3 26 3 26 120 152 232 1 }  { 4 2 4 5 0 0 0 1 }  { 4 6 4 6 240 248 248 1 }  { 4 7 4 9 184 216 248 1 }  { 4 7 5 8 184 216 248 1 }  { 4 7 6 7 184 216 248 1 }  { 4 10 4 10 120 152 232 1 }  { 4 12 5 16 184 216 248 1 }  { 4 14 9 16 184 216 248 1 }  { 4 14 10 15 184 216 248 1 }  { 4 17 4 18 0 0 0 1 }  { 4 25 4 25 120 152 232 1 }  { 4 26 5 26 64 96 184 1 }  { 5 1 5 1 0 0 0 1 }  { 5 2 5 2 120 152 232 1 }  { 5 3 5 3 184 216 248 1 }  { 5 4 6 4 120 152 232 1 }  { 5 6 5 8 184 216 248 1 }  { 5 9 5 9 120 152 232 1 }  { 5 10 5 10 104 128 216 1 }  { 5 12 5 18 184 216 248 1 }  { 5 14 6 18 184 216 248 1 }  { 5 14 8 17 184 216 248 1 }  { 5 19 5 20 0 0 0 1 }  { 5 25 5 26 64 96 184 1 }  { 6 0 8 0 0 0 0 1 }  { 6 1 6 1 120 152 232 1 }  { 6 2 6 2 184 216 248 1 }  { 6 3 6 4 120 152 232 1 }  { 6 5 6 6 0 0 0 1 }  { 6 8 6 8 120 152 232 1 }  { 6 9 6 9 104 128 216 1 }  { 6 10 6 10 0 0 0 1 }  { 6 11 6 13 104 128 216 1 }  { 6 14 6 19 184 216 248 1 }  { 6 20 10 20 240 248 248 1 }  { 6 21 6 21 0 0 0 1 }  { 6 25 6 26 0 0 0 1 }  { 7 1 7 1 184 216 248 1 }  { 7 2 7 3 120 152 232 1 }  { 7 2 9 2 120 152 232 1 }  { 7 4 7 4 0 0 0 1 }  { 7 5 19 6 184 216 248 1 }  { 7 7 7 9 0 0 0 1 }  { 7 10 8 17 184 216 248 1 }  { 7 18 7 18 104 128 216 1 }  { 7 19 9 21 240 248 248 1 }  { 7 22 7 22 0 0 0 1 }  { 8 1 8 2 120 152 232 1 }  { 8 3 10 3 0 0 0 1 }  { 8 4 8 17 184 216 248 1 }  { 8 4 13 9 184 216 248 1 }  { 8 4 21 4 184 216 248 1 }  { 8 18 8 22 240 248 248 1 }  { 8 18 9 21 240 248 248 1 }  { 8 18 10 20 240 248 248 1 }  { 8 23 9 23 0 0 0 1 }  { 9 1 9 1 0 0 0 1 }  { 9 10 9 13 104 128 216 1 }  { 9 17 9 21 240 248 248 1 }  { 9 17 10 20 240 248 248 1 }  { 9 17 13 17 240 248 248 1 }  { 9 22 19 22 184 216 248 1 }  { 10 2 10 3 0 0 0 1 }  { 10 2 11 2 0 0 0 1 }  { 10 4 10 15 184 216 248 1 }  { 10 4 11 11 184 216 248 1 }  { 10 4 12 10 184 216 248 1 }  { 10 16 10 20 240 248 248 1 }  { 10 16 11 19 240 248 248 1 }  { 10 16 12 18 240 248 248 1 }  { 10 21 17 23 184 216 248 1 }  { 10 24 11 24 0 0 0 1 }  { 11 3 11 11 184 216 248 1 }  { 11 3 12 10 184 216 248 1 }  { 11 3 19 6 184 216 248 1 }  { 11 3 20 5 184 216 248 1 }  { 11 12 11 14 0 0 0 1 }  { 11 15 11 19 240 248 248 1 }  { 11 20 17 23 184 216 248 1 }  { 12 1 18 1 0 0 0 1 }  { 12 2 12 10 184 216 248 1 }  { 12 2 13 9 184 216 248 1 }  { 12 2 17 8 184 216 248 1 }  { 12 2 18 7 184 216 248 1 }  { 12 11 12 11 0 0 0 1 }  { 12 15 12 15 0 0 0 1 }  { 12 19 16 24 184 216 248 1 }  { 12 25 18 25 0 0 0 1 }  { 13 10 13 10 0 0 0 1 }  { 13 16 13 16 0 0 0 1 }  { 13 18 16 24 184 216 248 1 }  { 13 18 17 23 184 216 248 1 }  { 13 18 19 22 184 216 248 1 }  { 14 9 16 9 0 0 0 1 }  { 14 17 16 17 0 0 0 1 }  { 17 9 21 9 240 248 248 1 }  { 17 10 17 10 0 0 0 1 }  { 17 16 17 16 0 0 0 1 }  { 17 17 17 23 184 216 248 1 }  { 17 17 19 22 184 216 248 1 }  { 17 24 17 24 120 152 232 1 }  { 17 29 17 30 0 0 0 1 }  { 18 8 20 10 240 248 248 1 }  { 18 11 18 11 0 0 0 1 }  { 18 15 18 15 0 0 0 1 }  { 18 16 19 22 184 216 248 1 }  { 18 16 21 21 184 216 248 1 }  { 18 23 19 23 120 152 232 1 }  { 18 24 18 24 104 128 216 1 }  { 18 28 22 28 0 0 0 1 }  { 18 29 20 29 240 248 248 1 }  { 18 30 18 30 184 216 248 1 }  { 18 31 22 32 0 0 0 1 }  { 19 2 20 2 0 0 0 1 }  { 19 7 19 11 240 248 248 1 }  { 19 7 20 10 240 248 248 1 }  { 19 12 19 14 0 0 0 1 }  { 19 15 19 22 184 216 248 1 }  { 19 15 21 21 184 216 248 1 }  { 19 24 20 24 0 0 0 1 }  { 19 29 19 30 240 248 248 1 }  { 20 6 20 10 240 248 248 1 }  { 20 6 21 9 240 248 248 1 }  { 20 6 22 8 240 248 248 1 }  { 20 6 24 6 240 248 248 1 }  { 20 11 21 21 184 216 248 1 }  { 20 11 22 20 184 216 248 1 }  { 20 11 24 17 184 216 248 1 }  { 20 22 21 22 120 152 232 1 }  { 20 23 20 23 104 128 216 1 }  { 20 30 20 30 184 216 248 1 }  { 21 3 22 3 0 0 0 1 }  { 21 5 21 9 240 248 248 1 }  { 21 5 22 8 240 248 248 1 }  { 21 5 23 7 240 248 248 1 }  { 21 10 21 21 184 216 248 1 }  { 21 10 22 20 184 216 248 1 }  { 21 10 26 13 184 216 248 1 }  { 21 23 22 23 0 0 0 1 }  { 21 29 21 29 184 216 248 1 }  { 21 30 22 30 120 152 232 1 }  { 22 4 22 8 240 248 248 1 }  { 22 9 22 20 184 216 248 1 }  { 22 9 23 19 184 216 248 1 }  { 22 9 24 17 184 216 248 1 }  { 22 21 22 21 120 152 232 1 }  { 22 22 22 22 104 128 216 1 }  { 22 29 22 30 120 152 232 1 }  { 23 4 23 4 0 0 0 1 }  { 23 8 23 19 184 216 248 1 }  { 23 8 24 17 184 216 248 1 }  { 23 8 25 15 184 216 248 1 }  { 23 20 23 20 120 152 232 1 }  { 23 21 23 21 104 128 216 1 }  { 23 22 23 22 0 0 0 1 }  { 23 29 23 30 0 0 0 1 }  { 24 5 24 5 0 0 0 1 }  { 24 7 24 17 184 216 248 1 }  { 24 18 24 19 120 152 232 1 }  { 24 20 24 20 104 128 216 1 }  { 24 21 24 21 0 0 0 1 }  { 25 6 25 7 0 0 0 1 }  { 25 16 25 17 120 152 232 1 }  { 25 18 25 18 104 128 216 1 }  { 25 19 25 20 0 0 0 1 }  { 26 8 26 9 0 0 0 1 }  { 26 14 26 15 120 152 232 1 }  { 26 16 26 16 104 128 216 1 }  { 26 17 26 18 0 0 0 1 }  { 27 10 27 16 0 0 0 1 }  ]
+  [  { 0 0 0 0 0 0 0 1 }  { 0 25 0 26 0 0 0 1 }  { 1 7 1 9 0 0 0 1 }  { 1 24 5 24 0 0 0 1 }  { 1 25 3 25 184 216 248 1 }  { 1 26 1 26 120 152 232 1 }  { 1 27 5 27 0 0 0 1 }  { 2 6 2 6 0 0 0 1 }  { 2 7 2 7 184 216 248 1 }  { 2 8 2 8 240 248 248 1 }  { 2 9 4 9 184 216 248 1 }  { 2 10 2 10 0 0 0 1 }  { 2 25 2 26 184 216 248 1 }  { 3 5 6 5 0 0 0 1 }  { 3 6 3 6 184 216 248 1 }  { 3 7 3 7 240 248 248 1 }  { 3 8 3 10 184 216 248 1 }  { 3 8 4 9 184 216 248 1 }  { 3 11 3 16 0 0 0 1 }  { 3 11 5 11 0 0 0 1 }  { 3 26 3 26 120 152 232 1 }  { 4 2 4 5 0 0 0 1 }  { 4 6 4 6 240 248 248 1 }  { 4 7 4 9 184 216 248 1 }  { 4 7 5 8 184 216 248 1 }  { 4 7 6 7 184 216 248 1 }  { 4 10 4 10 120 152 232 1 }  { 4 12 5 16 184 216 248 1 }  { 4 14 9 16 184 216 248 1 }  { 4 14 10 15 184 216 248 1 }  { 4 17 4 18 0 0 0 1 }  { 4 25 4 25 120 152 232 1 }  { 4 26 5 26 64 96 184 1 }  { 5 1 5 1 0 0 0 1 }  { 5 2 5 2 120 152 232 1 }  { 5 3 5 3 184 216 248 1 }  { 5 4 6 4 120 152 232 1 }  { 5 6 5 8 184 216 248 1 }  { 5 9 5 9 120 152 232 1 }  { 5 10 5 10 104 128 216 1 }  { 5 12 5 18 184 216 248 1 }  { 5 14 6 18 184 216 248 1 }  { 5 14 8 17 184 216 248 1 }  { 5 19 5 20 0 0 0 1 }  { 5 25 5 26 64 96 184 1 }  { 6 0 8 0 0 0 0 1 }  { 6 1 6 1 120 152 232 1 }  { 6 2 6 2 184 216 248 1 }  { 6 3 6 4 120 152 232 1 }  { 6 5 6 6 0 0 0 1 }  { 6 8 6 8 120 152 232 1 }  { 6 9 6 9 104 128 216 1 }  { 6 10 6 10 0 0 0 1 }  { 6 11 6 13 104 128 216 1 }  { 6 14 6 19 184 216 248 1 }  { 6 20 10 20 240 248 248 1 }  { 6 21 6 21 0 0 0 1 }  { 6 25 6 26 0 0 0 1 }  { 7 1 7 1 184 216 248 1 }  { 7 2 7 3 120 152 232 1 }  { 7 2 9 2 120 152 232 1 }  { 7 4 7 4 0 0 0 1 }  { 7 5 19 6 184 216 248 1 }  { 7 7 7 9 0 0 0 1 }  { 7 10 8 17 184 216 248 1 }  { 7 18 7 18 104 128 216 1 }  { 7 19 9 21 240 248 248 1 }  { 7 22 7 22 0 0 0 1 }  { 8 1 8 2 120 152 232 1 }  { 8 3 10 3 0 0 0 1 }  { 8 4 8 17 184 216 248 1 }  { 8 4 13 9 184 216 248 1 }  { 8 4 21 4 184 216 248 1 }  { 8 18 8 22 240 248 248 1 }  { 8 18 9 21 240 248 248 1 }  { 8 18 10 20 240 248 248 1 }  { 8 23 9 23 0 0 0 1 }  { 9 1 9 1 0 0 0 1 }  { 9 10 9 13 104 128 216 1 }  { 9 17 9 21 240 248 248 1 }  { 9 17 10 20 240 248 248 1 }  { 9 17 13 17 240 248 248 1 }  { 9 22 19 22 184 216 248 1 }  { 10 2 10 3 0 0 0 1 }  { 10 2 11 2 0 0 0 1 }  { 10 4 10 15 184 216 248 1 }  { 10 4 11 11 184 216 248 1 }  { 10 4 12 10 184 216 248 1 }  { 10 16 10 20 240 248 248 1 }  { 10 16 11 19 240 248 248 1 }  { 10 16 12 18 240 248 248 1 }  { 10 21 17 23 184 216 248 1 }  { 10 24 11 24 0 0 0 1 }  { 11 3 11 11 184 216 248 1 }  { 11 3 12 10 184 216 248 1 }  { 11 3 19 6 184 216 248 1 }  { 11 3 20 5 184 216 248 1 }  { 11 12 11 14 0 0 0 1 }  { 11 15 11 19 240 248 248 1 }  { 11 20 17 23 184 216 248 1 }  { 12 1 18 1 0 0 0 1 }  { 12 2 12 10 184 216 248 1 }  { 12 2 13 9 184 216 248 1 }  { 12 2 17 8 184 216 248 1 }  { 12 2 18 7 184 216 248 1 }  { 12 11 12 11 0 0 0 1 }  { 12 15 12 15 0 0 0 1 }  { 12 19 16 24 184 216 248 1 }  { 12 25 18 25 0 0 0 1 }  { 13 10 13 10 0 0 0 1 }  { 13 16 13 16 0 0 0 1 }  { 13 18 16 24 184 216 248 1 }  { 13 18 17 23 184 216 248 1 }  { 13 18 19 22 184 216 248 1 }  { 14 9 16 9 0 0 0 1 }  { 14 17 16 17 0 0 0 1 }  { 17 9 21 9 240 248 248 1 }  { 17 10 17 10 0 0 0 1 }  { 17 16 17 16 0 0 0 1 }  { 17 17 17 23 184 216 248 1 }  { 17 17 19 22 184 216 248 1 }  { 17 24 17 24 120 152 232 1 }  { 17 29 17 30 0 0 0 1 }  { 18 8 20 10 240 248 248 1 }  { 18 11 18 11 0 0 0 1 }  { 18 15 18 15 0 0 0 1 }  { 18 16 19 22 184 216 248 1 }  { 18 16 21 21 184 216 248 1 }  { 18 23 19 23 120 152 232 1 }  { 18 24 18 24 104 128 216 1 }  { 18 28 22 28 0 0 0 1 }  { 18 29 20 29 240 248 248 1 }  { 18 30 18 30 184 216 248 1 }  { 18 31 22 32 0 0 0 1 }  { 19 2 20 2 0 0 0 1 }  { 19 7 19 11 240 248 248 1 }  { 19 7 20 10 240 248 248 1 }  { 19 12 19 14 0 0 0 1 }  { 19 15 19 22 184 216 248 1 }  { 19 15 21 21 184 216 248 1 }  { 19 24 20 24 0 0 0 1 }  { 19 29 19 30 240 248 248 1 }  { 20 6 20 10 240 248 248 1 }  { 20 6 21 9 240 248 248 1 }  { 20 6 22 8 240 248 248 1 }  { 20 6 24 6 240 248 248 1 }  { 20 11 21 21 184 216 248 1 }  { 20 11 22 20 184 216 248 1 }  { 20 11 24 17 184 216 248 1 }  { 20 22 21 22 120 152 232 1 }  { 20 23 20 23 104 128 216 1 }  { 20 30 20 30 184 216 248 1 }  { 21 3 22 3 0 0 0 1 }  { 21 5 21 9 240 248 248 1 }  { 21 5 22 8 240 248 248 1 }  { 21 5 23 7 240 248 248 1 }  { 21 10 21 21 184 216 248 1 }  { 21 10 22 20 184 216 248 1 }  { 21 10 26 13 184 216 248 1 }  { 21 23 22 23 0 0 0 1 }  { 21 29 21 29 184 216 248 1 }  { 21 30 22 30 120 152 232 1 }  { 22 4 22 8 240 248 248 1 }  { 22 9 22 20 184 216 248 1 }  { 22 9 23 19 184 216 248 1 }  { 22 9 24 17 184 216 248 1 }  { 22 21 22 21 120 152 232 1 }  { 22 22 22 22 104 128 216 1 }  { 22 29 22 30 120 152 232 1 }  { 23 4 23 4 0 0 0 1 }  { 23 8 23 19 184 216 248 1 }  { 23 8 24 17 184 216 248 1 }  { 23 8 25 15 184 216 248 1 }  { 23 20 23 20 120 152 232 1 }  { 23 21 23 21 104 128 216 1 }  { 23 22 23 22 0 0 0 1 }  { 23 29 23 30 0 0 0 1 }  { 24 5 24 5 0 0 0 1 }  { 24 7 24 17 184 216 248 1 }  { 24 18 24 19 120 152 232 1 }  { 24 20 24 20 104 128 216 1 }  { 24 21 24 21 0 0 0 1 }  { 25 6 25 7 0 0 0 1 }  { 25 16 25 17 120 152 232 1 }  { 25 18 25 18 104 128 216 1 }  { 25 19 25 20 0 0 0 1 }  { 26 8 26 9 0 0 0 1 }  { 26 14 26 15 120 152 232 1 }  { 26 16 26 16 104 128 216 1 }  { 26 17 26 18 0 0 0 1 }  { 27 10 27 16 0 0 0 1 }  ]
 }
diff --git a/imperative-shell/file-thread.sml b/imperative-shell/file-thread.sml
index 3dcec95..98f2cf2 100644
--- a/imperative-shell/file-thread.sml
+++ b/imperative-shell/file-thread.sml
@@ -49,10 +49,10 @@ struct
     let
       val _ =
         case Mailbox.recv fileMailbox of
-          SAVE_SQUARES str => saveString (filename, str)
-        | EXPORT_SQUARES str => saveString (exportFilename, str)
-        | EXPORT_COLLISIONS str => saveString (collisionFilename, str)
-        | LOAD_SQUARES => loadSquares (filename, inputMailbox)
+          SAVE_SQUARES {filepath, output} => saveString (filepath, output)
+        | EXPORT_SQUARES {filepath, output} => saveString (filepath, output)
+        | EXPORT_COLLISIONS {filepath, output} => saveString (filepath, output)
+        | LOAD_SQUARES filename => loadSquares (filename, inputMailbox)
     in
       run (fileMailbox, inputMailbox)
     end
diff --git a/message-types/file-msg.sml b/message-types/file-msg.sml
index d2a966d..50dace2 100644
--- a/message-types/file-msg.sml
+++ b/message-types/file-msg.sml
@@ -1,8 +1,8 @@
 structure FileMessage =
 struct
   datatype t =
-    SAVE_SQUARES of string
-  | LOAD_SQUARES
-  | EXPORT_SQUARES of string
-  | EXPORT_COLLISIONS of string
+    SAVE_SQUARES of {output: string, filepath: string}
+  | LOAD_SQUARES of {filepath: string}
+  | EXPORT_SQUARES of {output: string, filepath: string}
+  | EXPORT_COLLISIONS of {output: string, filepath: string}
 end