diff --git a/hsqml-demo-morris.cabal b/hsqml-demo-morris.cabal
--- a/hsqml-demo-morris.cabal
+++ b/hsqml-demo-morris.cabal
@@ -1,5 +1,5 @@
 Name:          hsqml-demo-morris
-Version:       0.3.0.0
+Version:       0.3.1.0
 Cabal-version: >= 1.10
 Build-type:    Simple
 License:       BSD3
@@ -27,10 +27,9 @@
         containers >= 0.4 && < 0.6,
         deepseq    >= 1.2 && < 1.4,
         directory  >= 1.1 && < 1.3,
-        text       >= 0.11 && < 1.2,
-        tagged     >= 0.4 && < 0.8,
+        text       >= 0.11 && < 1.3,
         OddWord    == 1.0.*,
-        hsqml      == 0.3.*
+        hsqml      >= 0.3.1 && < 0.4
     GHC-options: -threaded
 
 Source-repository head
diff --git a/qml/morris.js b/qml/morris.js
--- a/qml/morris.js
+++ b/qml/morris.js
@@ -1,18 +1,11 @@
 var game = null;
-var prevGame = null;
 var redAI = 0;
 var blackAI = 2;
 var aiMove = [];
 
 function updateTargets()
 {
-    var next = game.targets;
-    var count = next.count;
-    var targets = [];
-    for (var i=0; i<count; i++) {
-        targets.push(next.elem(i));
-    }
-    targetView.model = targets;
+    targetView.model = game.targets;
 }
 
 function clearTargets()
@@ -22,29 +15,9 @@
 
 function updatePieces()
 {
-    var count = game.indexCount;
-    var pieces = [];
-    var hasAnim = false;
-    for (var i=0; i<count; i++) {
-        var currIdx = game.idxPosition(i);
-        var prevIdx = prevGame.idxPosition(i);
-
-        if (-1 != prevIdx || -1 != currIdx) {
-            var startIdx = (-1 != prevIdx) ? prevIdx : currIdx;
-            var endIdx = (-1 != currIdx) ? currIdx : prevIdx;
-            var startVis = (-1 != prevIdx) ? 1 : 0;
-            var endVis = (-1 != currIdx) ? 1 : 0;
-            hasAnim |= (startIdx != endIdx) || (startVis != endVis);
-            pieces.push({
-                startIdx: startIdx,
-                endIdx: endIdx,
-                startVis: startVis,
-                endVis: endVis,
-                red: 'red' == game.idxPlayer(i)});
-        }
-    }
-    pieceView.model = pieces;
-    if (hasAnim) {
+    pieceView.model = game.pieces;
+    var actions = game.actions.length;
+    if (actions == 0 || actions == 2) {
         anim.restart();
     }
     else {
@@ -55,14 +28,12 @@
 function setupGame()
 {
     game = createGame();
-    prevGame = game;
     updateTargets();
     updatePieces();
 }
 
 function selectTarget(i)
 {
-    prevGame = game;
     game = game.selectTarget(i);
     clearTargets();
     updatePieces();
@@ -87,11 +58,11 @@
 
 function aiReadyCallback(move)
 {
-    if (move.count == 0) {
+    if (move.length == 0) {
         return;
     }
-    for (var j=move.count-1; j>=0; j--) {
-        aiMove.push(move.elem(j));
+    for (var j=move.length-1; j>=0; j--) {
+        aiMove.push(move[j]);
     }
     animFinished();
 }
diff --git a/qml/morris.qml b/qml/morris.qml
--- a/qml/morris.qml
+++ b/qml/morris.qml
@@ -4,9 +4,19 @@
 Image {
     id: board;
     source: "board.svg";
-    fillMode: Image.PreserveAspectFit;
-    anchors.fill: parent;
+    width: 320; height: 320;
 
+    property real pw : parent!=null?parent.width:width;
+    property real ph : parent!=null?parent.height:height;
+
+    transform: [
+        Scale {
+            id: scale; xScale: yScale;
+            yScale: Math.min(board.pw/board.width,board.ph/board.height);},
+        Translate {
+            x: (board.pw-board.width*scale.xScale)/2;
+            y: (board.ph-board.height*scale.yScale)/2;}]
+
     property real t;
 
     NumberAnimation on t {
@@ -30,10 +40,10 @@
         id: pieceView
         model: [];
         Image {
-            source: modelData.red ? "red.svg" : "black.svg";
-            opacity: (modelData.endVis*board.t)+(modelData.startVis*(1-board.t));
-            x: (Morris.posIdToX(modelData.endIdx)*board.t)+(Morris.posIdToX(modelData.startIdx)*(1-board.t))-width/2;
-            y: (Morris.posIdToY(modelData.endIdx)*board.t)+(Morris.posIdToY(modelData.startIdx)*(1-board.t))-height/2;
+            source: modelData.player == "red" ? "red.svg" : "black.svg";
+            opacity: ((modelData.currPos!=null?1:0)*board.t)+((modelData.prevPos!=null?1:0)*(1-board.t));
+            x: (Morris.posIdToX(modelData.currPos!=null?modelData.currPos:modelData.prevPos)*board.t)+(Morris.posIdToX(modelData.prevPos!=null?modelData.prevPos:modelData.currPos)*(1-board.t))-width/2;
+            y: (Morris.posIdToY(modelData.currPos!=null?modelData.currPos:modelData.prevPos)*board.t)+(Morris.posIdToY(modelData.prevPos!=null?modelData.prevPos:modelData.currPos)*(1-board.t))-height/2;
         }
     }
 
diff --git a/src/Morris/Main.hs b/src/Morris/Main.hs
--- a/src/Morris/Main.hs
+++ b/src/Morris/Main.hs
@@ -54,14 +54,6 @@
 playActionId player (FirstAction act) = playFirstActionId player act
 playActionId _ (SecondAction act) = playSecondActionId act
 
-getIdBoardCount :: IdBoard -> Int
-getIdBoardCount (IdBoard m) =
-    if IntMap.null m then 0 else (1+) $ fst $ IntMap.findMax m
-
-getIdBoardPiece :: Int -> IdBoard -> Maybe (Player,Position)
-getIdBoardPiece i (IdBoard m) =
-    IntMap.lookup i m
-
 moveToActions :: Move -> [Action]
 moveToActions (FullMove act1 Nothing) =
     [FirstAction act1]
@@ -76,57 +68,74 @@
 moveToPositions :: Move -> [Position]
 moveToPositions = concatMap actionToPositions . moveToActions
 
-data PosListObj = PosListObj [Position] deriving Typeable
-
-posListElem :: PosListObj -> Int -> IO Int
-posListElem (PosListObj posList) idx =
-    return $ (\(Position i) -> i) $ posList !! idx
-
-posListCount :: PosListObj -> IO Int
-posListCount (PosListObj posList) =
-    return $ length posList
-
-instance DefaultClass PosListObj where
-    classMembers = [
-        defMethod "elem" posListElem,
-        defPropertyRO "count" posListCount]
+instance Marshal Player where
+    type MarshalMode Player c d = ModeBidi c
+    marshaller = bidiMarshaller from to
+        where from txt = case T.unpack txt of
+                  "red" -> Red
+                  _     -> Black
+              to plyr = T.pack $ case plyr of
+                  Red   -> "red"
+                  Black -> "black"
 
-instance Marshal PosListObj where
-    type MarshalMode PosListObj c d = ModeObjFrom PosListObj c
-    marshaller = fromMarshaller fromObjRef
+instance Marshal Position where
+    type MarshalMode Position c d = ModeBidi c
+    marshaller = bidiMarshaller Position (\(Position i) -> i)
 
 data GameObj = GameObj {
     gameBoard :: Board,
     gameIdBoard :: IdBoard,
     gameActions :: [Position],
-    gameBias :: Map Board Float}
+    gameBias :: Map Board Float,
+    gamePrev :: Maybe GameObj}
     deriving Typeable
 
-getPlayer :: GameObj -> IO Text
-getPlayer gs =
-    return $ case getBoardNextPlayer $ gameBoard gs of
-        Red   -> T.pack "red"
-        Black -> T.pack "black"
+data PieceObj = PieceObj {
+    piecePlayer :: Player,
+    piecePrevPos :: Maybe Position,
+    pieceCurrPos :: Maybe Position}
+    deriving (Typeable, Show)
+
+instance DefaultClass PieceObj where
+    classMembers = [
+        defPropertyConst "player" $ return . piecePlayer,
+        defPropertyConst "currPos" $ return . pieceCurrPos,
+        defPropertyConst "prevPos" $ return . piecePrevPos]
+
+instance Marshal PieceObj where
+    type MarshalMode PieceObj c d = ModeObjFrom PieceObj c
+    marshaller = fromMarshaller fromObjRef
+
+getPlayer :: GameObj -> IO Player
+getPlayer = return . getBoardNextPlayer . gameBoard
+
+getPieces :: GameObj -> IO [ObjRef PieceObj]
+getPieces gs =
+    let (IdBoard ib) = gameIdBoard $ fromMaybe gs $ gamePrev gs
+        (IdBoard ib') = gameIdBoard gs
+        merge _ (plyr,p) (_,p') = Just $ PieceObj plyr (Just p) (Just p')
+        oldMap = fmap $ \(plyr,p) -> PieceObj plyr (Just p) Nothing
+        newMap = fmap $ \(plyr,p') -> PieceObj plyr Nothing (Just p')
+        ps = IntMap.elems $ IntMap.mergeWithKey merge oldMap newMap ib ib'
+    in mapM newObjectDC ps
  
-getTargets :: GameObj -> IO (ObjRef PosListObj)
+getTargets :: GameObj -> IO [Position]
 getTargets gs =
     let actions = gameActions gs
         posOff  = length actions
-    in newObjectDC $ PosListObj $ nub $ map (!! posOff) $
+    in return $ nub $ map (!! posOff) $
         filter (isPrefixOf actions) $ map moveToPositions $
         legalMoves $ gameBoard gs
 
-getActions :: GameObj -> IO (ObjRef PosListObj)
-getActions gs =
-    newObjectDC $ PosListObj $ gameActions gs
+getActions :: GameObj -> IO [Position]
+getActions = return . gameActions
 
 startAI :: ObjRef GameObj -> Int -> IO ()
 startAI gsRef d = fmap (const ()) $ forkIO $ do
     let gs = fromObjRef gsRef
         ps = maybe [] moveToPositions $ aiMove d (gameBias gs) $ gameBoard gs
     evaluate $ force ps
-    posObj <- newObjectDC $ PosListObj ps
-    fireSignal (Proxy :: Proxy AIReady) gsRef posObj
+    fireSignal (Proxy :: Proxy AIReady) gsRef ps
 
 selectTarget :: GameObj -> Int -> IO (ObjRef GameObj)
 selectTarget gs i =
@@ -149,62 +158,40 @@
             gameIdBoard = iboard',
             gameActions = [],
             gameBias = {-Map.map (*0.9) $-} Map.alter (\x ->
-                Just $ fromMaybe 0 x - 0.5) board' $ gameBias gs}
+                Just $ fromMaybe 0 x - 0.5) board' $ gameBias gs,
+            gamePrev = Just gs}
         Nothing -> gs {
             gameIdBoard = iboard',
-            gameActions = actions'}
-
-getIndexCount :: GameObj -> IO Int
-getIndexCount gs =
-    return $ getIdBoardCount $ gameIdBoard gs
-
-getPlayerAtIndex :: GameObj -> Int -> IO Text
-getPlayerAtIndex gs i =
-    return $ case getIdBoardPiece i $ gameIdBoard gs of
-        Nothing -> T.pack "none"
-        Just (Red,_) -> T.pack "red"
-        Just (Black,_) -> T.pack "black"
-
-getPositionAtIndex :: GameObj -> Int -> IO Int
-getPositionAtIndex gs i =
-    return $ case getIdBoardPiece i $ gameIdBoard gs of
-        Nothing -> -1
-        Just (_,Position pos) -> pos
+            gameActions = actions',
+            gamePrev = Just gs}
 
 data AIReady deriving Typeable
 
 instance SignalKeyClass AIReady where
-    type SignalParams AIReady = ObjRef PosListObj -> IO ()
+    type SignalParams AIReady = [Position] -> IO ()
 
 instance DefaultClass GameObj where
     classMembers = [
         defPropertyRO "player" getPlayer,
+        defPropertyRO "pieces" getPieces,
         defPropertyRO "targets" getTargets,
         defPropertyRO "actions" getActions,
         defMethod "startAI" startAI,
         defSignal "aiReady" (Proxy :: Proxy AIReady),
-        defMethod "selectTarget" selectTarget,
-        defPropertyRO "indexCount" getIndexCount,
-        defMethod "idxPlayer" getPlayerAtIndex,
-        defMethod "idxPosition" getPositionAtIndex]
+        defMethod "selectTarget" selectTarget]
 
 instance Marshal GameObj where
     type MarshalMode GameObj c d = ModeObjFrom GameObj c
     marshaller = fromMarshaller fromObjRef
 
-createGame :: ObjRef MainObj -> IO (ObjRef GameObj)
+createGame :: ObjRef () -> IO (ObjRef GameObj)
 createGame _ =
-    newObjectDC $ GameObj newBoard newIdBoard [] Map.empty
-
-data MainObj = MainObj deriving Typeable
-
-instance DefaultClass MainObj where
-    classMembers = [
-        defMethod "createGame" createGame]
+    newObjectDC $ GameObj newBoard newIdBoard [] Map.empty Nothing
 
 main :: IO ()
 main = do
-    ctx <- newObjectDC $ MainObj
+    clazz <- newClass [defMethod "createGame" createGame]
+    ctx <- newObject clazz ()
     qml <- getDataFileName "morris.qml"
     runEngineLoop defaultEngineConfig {
         initialDocument = fileDocument qml,