diff --git a/java/org/artisanlogiciel/games/maze/LabyMap.java b/java/org/artisanlogiciel/games/maze/LabyMap.java
index 74d5a0e..42d24fc 100644
--- a/java/org/artisanlogiciel/games/maze/LabyMap.java
+++ b/java/org/artisanlogiciel/games/maze/LabyMap.java
@@ -27,6 +27,11 @@ public class LabyMap implements WallsProvider
         return getAt(x, y).getWalls();
     }
 
+    public short getWalls(Position cell)
+    {
+        return getAt(cell.getX(), cell.getY()).getWalls();
+    }
+
     public int getWidth()
     {
         return tileMap[0].length;
diff --git a/java/org/artisanlogiciel/games/maze/LabyModel.java b/java/org/artisanlogiciel/games/maze/LabyModel.java
index edc9385..a926c48 100644
--- a/java/org/artisanlogiciel/games/maze/LabyModel.java
+++ b/java/org/artisanlogiciel/games/maze/LabyModel.java
@@ -79,7 +79,7 @@ lues, they are used as it is for
     boolean maxreached = false;
     java.util.Random random;
     // list of positions not fully walked
-    private final LinkedList<Position> openList = new LinkedList<Position>();
+    private final LinkedList<PositionWithDepth> openList = new LinkedList<>();
     // list of entries and exits.
     private final LinkedList<Position> entryExits = new LinkedList<Position>();
     private final Object coherentLock = new Object(); // before getting the lock
@@ -390,7 +390,7 @@ lues, they are used as it is for
         return this.height;
     }
 
-    public LinkedList<Position> getOpenList() {
+    public LinkedList<PositionWithDepth> getOpenList() {
         return openList;
     }
 
@@ -464,7 +464,7 @@ lues, they are used as it is for
                     t[x][y] &= ~OPEN;
                 }
                 if (isFlagSet(t[x][y], OPEN) || (t[x][y] == CLEAR)) {
-                    openList.add(new Position(x, y));
+                    openList.add(new PositionWithDepth(x, y,0));
                 }
             }
         }
@@ -477,7 +477,7 @@ lues, they are used as it is for
      **/
     public void generateWithEntry(int x, int y) {
 
-        openList.add(new Position(x, y));
+        openList.add(new PositionWithDepth(x, y,0));
         while (!openList.isEmpty()) {
             // this is where magic happens
             step();
@@ -493,7 +493,7 @@ lues, they are used as it is for
                     // should not continue in depth first...
                     if (!openList.isEmpty()) {
                         // insert head as next position to pick up.
-                        Position current = openList.removeFirst();
+                        PositionWithDepth current = openList.removeFirst();
                         openList.add(current);
                     }
                 }
@@ -526,7 +526,7 @@ lues, they are used as it is for
      * @param p Position
      * @return true if newly added , false if already open.
      **/
-    private boolean open(boolean first, Position p) {
+    private boolean open(boolean first, PositionWithDepth p) {
         int x = p.getX();
         int y = p.getY();
         if ((t[x][y] & OPEN) != OPEN) {
@@ -537,6 +537,7 @@ lues, they are used as it is for
         return false;
     }
 
+    // WARNING Brick uses argument in other order... ( bad ... )
     public final static boolean isFlagSet(short check, short flag) {
         return Brick.isFlagSet(flag,check);
     }
@@ -588,7 +589,7 @@ lues, they are used as it is for
      **/
     public boolean step() {
         boolean complete = false;
-        Position current = null;
+        PositionWithDepth current = null;
 
         synchronized (coherentLock) {
 
@@ -668,7 +669,7 @@ lues, they are used as it is for
                         newx = x;
                     }
 
-                    Position target = new Position(newx, newy, current.getDepth() + 1);
+                    PositionWithDepth target = new PositionWithDepth(newx, newy, current.getDepth() + 1);
                     open(false, target);
                     if ((t[x][y] & DIRECTION) == DIRECTION) {
                         t[x][y] |= direction;
@@ -707,6 +708,10 @@ lues, they are used as it is for
         return complete;
     }
 
+    public short getWalls(Position cell) {
+        return getWalls(cell.getX(), cell.getY());
+    }
+
     public short getWalls(int x, int y) {
         short walls = 0;
         for (short direction : AllDirections) {
diff --git a/java/org/artisanlogiciel/games/maze/Position.java b/java/org/artisanlogiciel/games/maze/Position.java
index 11d0801..250ddeb 100644
--- a/java/org/artisanlogiciel/games/maze/Position.java
+++ b/java/org/artisanlogiciel/games/maze/Position.java
@@ -4,22 +4,20 @@ package org.artisanlogiciel.games.maze;
 public class Position
 {
     private int x, y;
-    private int depth;
-
-    public Position(int x, int y, int depth)
-    {
-        this.x = x;
-        this.y = y;
-        this.depth = depth;
-    }
 
     public Position(int x, int y)
     {
         this.x = x;
         this.y = y;
-        this.depth = 0;
     }
 
+    public Position(Position other)
+    {
+        this.x = other.x;
+        this.y = other.y;
+    }
+
+
     public int getX()
     {
         return this.x;
@@ -30,29 +28,58 @@ public class Position
         return this.y;
     }
 
-    public int getDepth()
-    {
-        return depth;
+    public Position translate(Position other) {
+        return new Position(x + other.x, y + other.y);
     }
 
+    public Position doTranslate(Position other) {
+        x += other.x;
+        y += other.y;
+        return this;
+    }
+
+
+    public void limitToMax(int mx, int my)
+    {
+        x = Math.min(x,mx);
+        y = Math.min(y,my);
+    }
+
+    public void limitToMin(int mx, int my)
+    {
+        x = Math.max(x,mx);
+        y = Math.max(y,my);
+    }
+
+    public Position setX(int x)
+    {
+        this.x = x;
+        return this;
+    }
+
+    public Position setY(int y)
+    {
+        this.y = y;
+        return this;
+    }
+
+
     public String toString()
     {
-        return "(" + x + "," + y + ")" + "/" + depth;
+        return "(" + x + "," + y + ")";
     }
 
     public boolean equals(Object other)
     {
-	// disregards depth
-	if (other instanceof Position )
-	    {
-		Position p = (Position) other;
-		return (p.getX() == x) && (p.getY() == y);
-	    }
-	else
-	    {
-		return false;
-	    }
-		
-		
+        // disregards depth
+        if (other instanceof Position )
+            {
+            Position p = (Position) other;
+            return (p.getX() == x) && (p.getY() == y);
+            }
+        else
+            {
+            return false;
+            }
     }
 }
diff --git a/java/org/artisanlogiciel/games/maze/PositionWithDepth.java b/java/org/artisanlogiciel/games/maze/PositionWithDepth.java
new file mode 100644
index 0000000..b52591b
--- /dev/null
+++ b/java/org/artisanlogiciel/games/maze/PositionWithDepth.java
@@ -0,0 +1,24 @@
+package org.artisanlogiciel.games.maze;
+
+public class PositionWithDepth
+extends Position
+{
+    private int depth;
+
+    public PositionWithDepth(int x, int y, int depth)
+    {
+        super(x,y);
+        this.depth = depth;
+    }
+
+    public int getDepth()
+    {
+        return depth;
+    }
+
+    public String toString()
+    {
+        return "(" + getX() + "," + getY() + ")" + "/" + depth;
+    }
+
+}
diff --git a/java/org/artisanlogiciel/games/maze/WallsProvider.java b/java/org/artisanlogiciel/games/maze/WallsProvider.java
index 968b4e8..e17ea2c 100644
--- a/java/org/artisanlogiciel/games/maze/WallsProvider.java
+++ b/java/org/artisanlogiciel/games/maze/WallsProvider.java
@@ -22,4 +22,6 @@ public interface WallsProvider
      *   t
      **/
     short getWalls(int x, int y);
+
+    short getWalls(Position cell);
 }
diff --git a/java/org/artisanlogiciel/games/maze/XYGridIterator.java b/java/org/artisanlogiciel/games/maze/XYGridIterator.java
new file mode 100644
index 0000000..9115e1f
--- /dev/null
+++ b/java/org/artisanlogiciel/games/maze/XYGridIterator.java
@@ -0,0 +1,46 @@
+package org.artisanlogiciel.games.maze;
+
+public class XYGridIterator {
+
+    final static Position stepX = new Position(1,0);
+    final static Position stepY = new Position( 0,1);
+
+    Position min;
+    Position max;
+
+    Position next;
+
+    public XYGridIterator(Position min, Position max) {
+        this.min = min;
+        this.max = max;
+        reset();
+    }
+
+    public void reset()
+    {
+        this.next = new Position(min);
+    }
+
+    public boolean hasNext()
+    {
+        return next != null;
+    }
+
+    public Position next()
+    {
+        if ( next != null)
+        {
+            Position current = new Position(next);
+            next.doTranslate(stepX);
+            if ( next.getX() >= max.getX()) {
+                if (next.getY() < max.getY() - 1) {
+                    next.setX(min.getX()).doTranslate(stepY);
+                } else {
+                    next = null;
+                }
+            }
+            return current;
+        }
+        return null;
+    }
+}
diff --git a/java/org/artisanlogiciel/games/maze/gui/CellGridComponent.java b/java/org/artisanlogiciel/games/maze/gui/CellGridComponent.java
new file mode 100644
index 0000000..dd33093
--- /dev/null
+++ b/java/org/artisanlogiciel/games/maze/gui/CellGridComponent.java
@@ -0,0 +1,19 @@
+package org.artisanlogiciel.games.maze.gui;
+
+import org.artisanlogiciel.games.maze.model.WidthHeightProvider;
+
+import javax.swing.*;
+
+public abstract class CellGridComponent
+extends JComponent {
+
+    MazeCellRenderer cp;
+
+    MazeCellRenderer createCellRenderer(boolean hexagon, WidthHeightProvider model, WidthHeightProvider frame)
+    {
+        MazeCellRenderer cellRenderer = hexagon ?
+                new HexagonCellRenderer(model, frame, 0, 0)
+                : new MazeCellRenderer(model, frame, 0, 0);
+        return cellRenderer;
+    }
+}
diff --git a/java/org/artisanlogiciel/games/maze/gui/Display.java b/java/org/artisanlogiciel/games/maze/gui/Display.java
index abd2c2d..adfd0f0 100644
--- a/java/org/artisanlogiciel/games/maze/gui/Display.java
+++ b/java/org/artisanlogiciel/games/maze/gui/Display.java
@@ -66,6 +66,11 @@ implements StatusListener
         maze.resetCellRenderer(hexagon, frameSize);
     }
 
+    public void setBackground(boolean background) {
+        addStatus(background ? "view background" : "hide background");
+        maze.setViewBackground(background);
+    }
+
     private class MazeFrame extends JFrame
     {
         MazeFrame(LabyModel model, WidthHeightProvider frame, MazeParams params) {
diff --git a/java/org/artisanlogiciel/games/maze/gui/HexagonCellRenderer.java b/java/org/artisanlogiciel/games/maze/gui/HexagonCellRenderer.java
index 5188c97..af51e49 100644
--- a/java/org/artisanlogiciel/games/maze/gui/HexagonCellRenderer.java
+++ b/java/org/artisanlogiciel/games/maze/gui/HexagonCellRenderer.java
@@ -1,6 +1,7 @@
 package org.artisanlogiciel.games.maze.gui;
 
 import org.artisanlogiciel.games.maze.Brick;
+import org.artisanlogiciel.games.maze.Position;
 import org.artisanlogiciel.games.maze.model.WidthHeightProvider;
 
 import java.awt.*;
@@ -20,15 +21,15 @@ extends MazeCellRenderer
         super(model, frame, x, y);
     }
 
-    void drawLine(Graphics g, int refx, int refy, int x, int y, int a, int b) {
+    void drawLine(Graphics g, Position ref, int x, int y, int a, int b) {
         g.drawLine(
-                (int) ((refx + x) * width / SUBCELL), (int) ((refy + y) * height / SUBCELL),
-                (int) ((refx + a) * width / SUBCELL),(int) ((refy + b) * height / SUBCELL));
+                (int) ((ref.getX() + x) * width / SUBCELL), (int) ((ref.getY() + y) * height / SUBCELL),
+                (int) ((ref.getX() + a) * width / SUBCELL),(int) ((ref.getY() + b) * height / SUBCELL));
     }
 
     @Override
-    public void drawBackground(Graphics g, int pX, int pY, short walls) {
-        UV uv= new UV(pX,pY);
+    public void drawBackground(Graphics g, Position cell, short walls) {
+        UV uv= new UV(cell);
         int x = offsetX + (int) (uv.getX() * width / SUBCELL);
         int y = offsetY + (int) (uv.getY() * height / SUBCELL);
         Color savecolor = g.getColor();
@@ -39,47 +40,39 @@ extends MazeCellRenderer
     }
 
     class UV
+        extends Position
     {
         int u;
         int v;
 
-        UV(int u, int v)
+        UV(Position p)
         {
-            this.u=u;
-            this.v=v;
-        }
-
-        int getX()
-        {
-            return u*4 + 2*(v%2);
-        }
-
-        int getY()
-        {
-            return 3*v;
+            super(p);
+            u=p.getX();
+            v=p.getY();
+            setX(u*4 + 2*(v%2));
+            setY(3*v);
         }
 
     }
 
     @Override
-    public void drawWalls(Graphics g, int pX, int pY, short walls) {
-        drawHalfNW(g, pX, pY, walls);
+    public void drawWalls(Graphics g, Position cell, short walls) {
+        drawHalfNW(g, cell, walls);
     }
 
-    void drawHalfNW(Graphics g, int refx, int refy, short walls)
+    void drawHalfNW(Graphics g, Position cell, short walls)
     {
-        UV uv= new UV(refx,refy);
-        int x = uv.getX();
-        int y = uv.getY();
+        UV uv= new UV(cell);
         // NW : (0,1) - (2,0)
         if (Brick.isFlagSet( Brick.UP, walls))
-            drawLine(g,x, y, 0,1,2,0);
+            drawLine(g,uv, 0,1,2,0);
         // W : (0,1) - (0,3)
         if (Brick.isFlagSet( Brick.LEFT, walls))
-            drawLine(g,x,y,0,1,0,3);
+            drawLine(g,uv,0,1,0,3);
         // NE : (2,0) - (4,1)
         // if (Brick.isFlagSet( Brick.NE, walls))
-        drawLine(g,x,y,2,0,4,1);
+        drawLine(g,uv,2,0,4,1);
     }
 
     void drawHalfSW(Graphics g)
diff --git a/java/org/artisanlogiciel/games/maze/gui/MazeCellRenderer.java b/java/org/artisanlogiciel/games/maze/gui/MazeCellRenderer.java
index 145cb9a..78ece3b 100644
--- a/java/org/artisanlogiciel/games/maze/gui/MazeCellRenderer.java
+++ b/java/org/artisanlogiciel/games/maze/gui/MazeCellRenderer.java
@@ -82,25 +82,25 @@ public class MazeCellRenderer {
                 Math.max(0,color.getBlue() - greylevel));
         return greyedColor;
     }
-    public void drawBackground(Graphics g, int pX, int pY, short walls) {
-        int x = offsetX + (int) (pX * width);
-        int y = offsetY + (int) (pY * height);
+    public void drawBackground(Graphics g, Position cell, short walls) {
+        int x = offsetX + (int) (cell.getX() * width);
+        int y = offsetY + (int) (cell.getY() * height);
         Color savecolor = g.getColor();
         int greylevel = walls << 2;
         g.setColor(getGreyedColor(savecolor,greylevel));
         //g.fillRect(x+1,y+1,((int)width) -1,((int)height) - 1);
         g.fillRect(x,y,((int)width),((int)height));
     }
-    public void drawWalls(Graphics g, int pX, int pY, short walls) {
-        int x = offsetX + (int) (pX * width);
-        int y = offsetY + (int) (pY * height);
-        if ((pY == 0) && ( Brick.isFlagSet( Brick.UP, walls)))
+    public void drawWalls(Graphics g, Position cell, short walls) {
+        int x = offsetX + (int) (cell.getX() * width);
+        int y = offsetY + (int) (cell.getY() * height);
+        if ((cell.getY() == 0) && ( Brick.isFlagSet( Brick.UP, walls)))
             g.drawLine(x, y, x + (int) width, y);
         if (Brick.isFlagSet( Brick.DOWN, walls))
             g.drawLine(x, y + (int) height, x + (int) width, y + (int) height);
         if (Brick.isFlagSet( Brick.RIGHT, walls))
             g.drawLine(x + (int) width, y, x + (int) width, y + (int) height);
-        if ((pX == 0) && (Brick.isFlagSet( Brick.LEFT, walls)))
+        if ((cell.getX() == 0) && (Brick.isFlagSet( Brick.LEFT, walls)))
             g.drawLine(x, y, x, y + (int) height);
     }
 
@@ -145,23 +145,23 @@ public class MazeCellRenderer {
         }
     }
 
-    public void drawDot(Graphics g, Position dot, int pX, int pY, int mX, int mY) {
+    public void drawDot(Graphics g, Position dot, Position min, Position max) {
         double h = getHeight();
         double radius = (h > width) ? width : h;
         int a = (int) (radius / 4);
-        if ((dot.getX() >= pX) && (dot.getY() >= pY) && (dot.getX() < mX) && (dot.getY() < mY)) {
+        if ((dot.getX() >= min.getX()) && (dot.getY() >= min.getY()) && (dot.getX() < max.getX()) && (dot.getY() < max.getY())) {
             int x = offsetX + (int) (dot.getX() * width);
             int y = offsetY + (int) (dot.getY() * h);
             int r2 = (int) radius ; //(int) ((radius * 3) / 4);
             g.drawOval(x, y, r2, r2);
-            // g.drawLine(x+a,y+a,x+width-a,y+height-a);
-            // g.drawLine(x+a,y+height-a,x+width-a,y+a);
-
-        } else {
-            int x = offsetX + (int) (pX * width);
-            int y = offsetY + (int) (pY * h);
+        }
+        /* why do we drwa anything at all ?
+        else {
+            int x = offsetX + (int) (min.getX() * width);
+            int y = offsetY + (int) (min.getY() * h);
             g.drawLine(x + 1, y + 1, x + (int) width - 1, y + (int) h - 1);
         }
+        */
     }
 
 }
diff --git a/java/org/artisanlogiciel/games/maze/gui/MazeColorMap.java b/java/org/artisanlogiciel/games/maze/gui/MazeColorMap.java
new file mode 100644
index 0000000..42b81e2
--- /dev/null
+++ b/java/org/artisanlogiciel/games/maze/gui/MazeColorMap.java
@@ -0,0 +1,19 @@
+package org.artisanlogiciel.games.maze.gui;
+
+import java.awt.*;
+
+public class MazeColorMap {
+    public Color background;
+    public Color wall;
+    public Color path;
+    public Color resolved_path;
+    public Color goal;
+
+    public MazeColorMap(Color background, Color wall, Color path, Color resolved_path, Color goal) {
+        this.background = background;
+        this.wall = wall;
+        this.path = path;
+        this.resolved_path = resolved_path;
+        this.goal = goal;
+    }
+}
diff --git a/java/org/artisanlogiciel/games/maze/gui/MazeComponent.java b/java/org/artisanlogiciel/games/maze/gui/MazeComponent.java
index a4f9207..5eb63f4 100644
--- a/java/org/artisanlogiciel/games/maze/gui/MazeComponent.java
+++ b/java/org/artisanlogiciel/games/maze/gui/MazeComponent.java
@@ -19,16 +19,16 @@ import java.util.Date;
 import java.util.LinkedList;
 
 public class MazeComponent
-        extends JComponent
+        extends CellGridComponent
         implements MazeCreationListener,
         MazeResolutionListener,
         MouseMotionListener,
         Scrollable
 {
     private static final long serialVersionUID = 3163272907991176390L;
+    private boolean viewBackground = true;
 
     LabyModelProvider map;
-    MazeCellRenderer cp;
     Position current = null;
     LinkedList<DirectionPosition> solvedPath = null;
     LinkedList<DirectionPosition> drawingPath = null;
@@ -52,33 +52,8 @@ public class MazeComponent
 
     StatusListener statusListener;
 
-    MazeCellRenderer createCellRenderer(boolean hexagon, WidthHeightProvider model, WidthHeightProvider frame)
-    {
-        MazeCellRenderer cellRenderer = hexagon ?
-                new HexagonCellRenderer(model, frame, 0, 0)
-                : new MazeCellRenderer(model, frame, 0, 0);
-        return cellRenderer;
-    }
-
     MazeColorMap colorMap = new MazeColorMap(Color.white, Color.black, Color.blue, Color.green, Color.red);
 
-    public class MazeColorMap
-    {
-        public Color background;
-        public Color wall;
-        public Color path;
-        public Color resolved_path;
-        public Color goal;
-
-        public MazeColorMap(Color background, Color wall, Color path, Color resolved_path, Color goal) {
-            this.background = background;
-            this.wall = wall;
-            this.path = path;
-            this.resolved_path = resolved_path;
-            this.goal = goal;
-        }
-    }
-
     public void setXpm(Xpm xpm)
     {
         this.xpm = xpm;
@@ -287,6 +262,15 @@ public class MazeComponent
         */
     }
 
+    public void setViewBackground(boolean viewBackground)
+    {
+        this.viewBackground = viewBackground;
+    }
+    private boolean hasBackground()
+    {
+        return viewBackground && (xpm != null);
+    }
+
     @Override
     protected void paintComponent(Graphics g) {
         super.paintComponent(g);
@@ -300,101 +284,95 @@ public class MazeComponent
         // Shape s=g.getClip();
         Rectangle r = g.getClipBounds();
 
-        int mX = (int) ((double) r.getWidth() / cp.getWidth());
-        int mY = (int) ((double) r.getHeight() / cp.getHeight());
-        int pX = (int) ((double) (r.getX() - cp.getOffsetX()) / cp.getWidth());
-        int pY = (int) ((double) (r.getY() - cp.getOffsetY()) / cp.getHeight());
+        // visible part of grid :
+        //     (min)-------------
+        //       |                |
+        //       _______________(max)
 
-        if (pX < 0)
-            pX = 0;
-        if (pY < 0)
-            pY = 0;
-        if (pX >= map.getWidth())
-            return;
-        if (pY >= map.getHeight())
+        Position min = new Position(
+                (int) ((double) (r.getX() - cp.getOffsetX()) / cp.getWidth()),
+                (int) ((double) (r.getY() - cp.getOffsetY()) / cp.getHeight())
+        );
+
+        min.limitToMin(0,0);
+
+        if ( (min.getX() >= map.getWidth()) || (min.getY() >= map.getHeight()) )
             return;
 
-        mX = mX + pX;
-        mY = mY + pY;
+        Position extent = new Position(
+                (int) ((double) r.getWidth() / cp.getWidth()),
+                (int) ((double) r.getHeight() / cp.getHeight())
+        );
+        Position max = min.translate(extent);
 
-        if (mX > map.getWidth()) {
-            mX = map.getWidth();
-        }
-        if (mY > map.getHeight()) {
-            mY = map.getHeight();
-        }
+        max.limitToMax(map.getWidth(), map.getHeight());
+
+        int mX = max.getX();
+        int mY = max.getY();
 
-        int aX = pX;
-        int aY = pY;
 
         // draw background
-        for (; pY < mY; pY++) {
-            for (pX = 0; pX < mX; pX++) {
-                walls = map.getWalls(pX, pY);
-                if ( xpm != null ) {
-                    int cX = ( pX < xpm.getWidth()) ? pX : xpm.getWidth() - 1;
-                    int cY = ( pY < xpm.getHeight()) ? pY : xpm.getHeight() - 1;
-                    g.setColor(xpm.getColor(cX,cY));
-                }
-                else {
-                    g.setColor(colorMap.background);
-                }
-                cp.drawBackground(g, pX, pY, walls);
+        XYGridIterator iterator = new XYGridIterator(min,max);
+        Position cell = null;
+        while ( ( cell = iterator.next())  != null )
+        {
+            walls = map.getWalls(cell);
+            if ( hasBackground() ) {
+                Position colored = new Position(cell);
+                colored.limitToMax(xpm.getWidth() - 1, xpm.getHeight() -1 );
+                g.setColor(xpm.getColor(colored.getX(), colored.getY()));
             }
+            else {
+                g.setColor(colorMap.background);
+            }
+            cp.drawBackground(g, cell, walls);
         }
 
         if ((sX == gX) && (sY == gY)) {
             g.setColor(colorMap.goal);
         } else {
             g.setColor(colorMap.resolved_path);
-            cp.drawDot(g, new Position(gX, gY), pX, pY, mX, mY);
+            cp.drawDot(g, new Position(gX, gY), min, max);
             g.setColor(colorMap.path);
         }
-        cp.drawDot(g, new Position(sX, sY), pX, pY, mX, mY);
-
-        pX = aX;
-        pY = aY;
+        cp.drawDot(g, new Position(sX, sY), min, max);
 
         // draw all walls within clip bounds horiz first then lines
         g.setColor(colorMap.wall);
-        for (; pY < mY; pY++) {
-            for (pX = 0; pX < mX; pX++) {
-                walls = map.getWalls(pX, pY);
-                cp.drawWalls(g, pX, pY, walls);
-            }
+        iterator.reset();
+        cell = null;
+        while ( ( cell = iterator.next())  != null )
+        {
+            cp.drawWalls(g, cell, map.getWalls(cell));
         }
 
         if (this.showAll) {
             statusListener.addStatus("*");
-            pX = aX;
-            pY = aY;
 
             // draw all path within clip bounds horiz first then lines
-            for (; pY < mY; pY++) {
-                for (pX = 0; pX < mX; pX++) {
-                    path = map.getPath(pX, pY);
-                    g.setColor(colorMap.path);
-                    if (path != 0) {
-                        DirectionPosition dp = new DirectionPosition(path, new Position(pX, pY));
-                        cp.drawPath(g, dp, pX, pY, pX + 1, pY + 1);
-                    }
+            iterator.reset();
+            cell = null;
+            while ( ( cell = iterator.next())  != null )
+            {
+                path = map.getPath(cell.getX(), cell.getY());
+                g.setColor(colorMap.path);
+                if (path != 0) {
+                    DirectionPosition dp = new DirectionPosition(path, new Position(cell));
+                    cp.drawPath(g, dp, cell.getX(), cell.getY(), cell.getX() + 1, cell.getY() + 1);
                 }
             }
         }
 
-        pX = aX;
-        pY = aY;
-
         synchronized (lockChange) {
             g.setColor(colorMap.goal);
             if (current != null) {
-                cp.drawDot(g, current, pX, pY, mX, mY);
+                cp.drawDot(g, current, min, max);
             }
             g.setColor(colorMap.resolved_path);
             if (solvedPath != null) {
                 for (DirectionPosition resolved : solvedPath) {
-                    cp.drawDot(g, resolved.getPosition(), pX, pY, mX, mY);
-                    cp.drawPath(g, resolved, pX, pY, mX, mY);
+                    cp.drawDot(g, resolved.getPosition(), min, max);
+                    cp.drawPath(g, resolved, min.getX(), min.getY(), mX, mY);
                 }
             }
         }
diff --git a/java/org/artisanlogiciel/games/maze/gui/MazeControler.java b/java/org/artisanlogiciel/games/maze/gui/MazeControler.java
index 5c86942..7bbb0fe 100644
--- a/java/org/artisanlogiciel/games/maze/gui/MazeControler.java
+++ b/java/org/artisanlogiciel/games/maze/gui/MazeControler.java
@@ -229,6 +229,11 @@ public class MazeControler extends JPanel {
         return newActionButton("load", format, action);
     }
 
+    private JPanel createPaletteChooser()
+    {
+        return new JPanel(new FlowLayout());
+    }
+
     private JPanel createResolveQuitBar() {
         JPanel resolveQuitBar = new JPanel(new FlowLayout());
 
@@ -388,6 +393,7 @@ public class MazeControler extends JPanel {
                 display.setAutoSize(autoSlide.isSelected());
             }
         });
+
         final JCheckBox hexagon = new JCheckBox("hexagon");
         hexagon.addChangeListener(new ChangeListener() {
             public void stateChanged(ChangeEvent e) {
@@ -395,11 +401,19 @@ public class MazeControler extends JPanel {
             }
         });
 
+        final JCheckBox background = new JCheckBox("background");
+        background.addChangeListener(new ChangeListener() {
+            public void stateChanged(ChangeEvent e) {
+                display.setBackground(background.isSelected());
+            }
+        });
+
         JPanel resizecontrol = new JPanel(new FlowLayout());
         resizecontrol.add(showAll);
         resizecontrol.add(slider);
         resizecontrol.add(autoSlide);
         resizecontrol.add(hexagon);
+        resizecontrol.add(background);
 
         return resizecontrol;
 
diff --git a/java/org/artisanlogiciel/games/maze/model/HalfSquareRasterModel.java b/java/org/artisanlogiciel/games/maze/model/HalfSquareRasterModel.java
index 9304128..d9c241b 100644
--- a/java/org/artisanlogiciel/games/maze/model/HalfSquareRasterModel.java
+++ b/java/org/artisanlogiciel/games/maze/model/HalfSquareRasterModel.java
@@ -1,6 +1,7 @@
 package org.artisanlogiciel.games.maze.model;
 
 import org.artisanlogiciel.games.maze.MovesProvider;
+import org.artisanlogiciel.games.maze.Position;
 import org.artisanlogiciel.games.maze.WallsProvider;
 
 /**
@@ -98,6 +99,12 @@ public class HalfSquareRasterModel
         );
     }
 
+    public short getWalls(Position cell)
+    {
+        return getWalls(cell.getX(), cell.getY());
+    }
+
+
     public short getMoves(int x, int y)
     {
         // moves are where there is no walls ...
diff --git a/java/org/artisanlogiciel/games/maze/model/LineColumnModel.java b/java/org/artisanlogiciel/games/maze/model/LineColumnModel.java
index 99ae194..948f553 100644
--- a/java/org/artisanlogiciel/games/maze/model/LineColumnModel.java
+++ b/java/org/artisanlogiciel/games/maze/model/LineColumnModel.java
@@ -2,6 +2,7 @@ package org.artisanlogiciel.games.maze.model;
 
 import org.artisanlogiciel.games.maze.Brick;
 import org.artisanlogiciel.games.maze.MovesProvider;
+import org.artisanlogiciel.games.maze.Position;
 import org.artisanlogiciel.games.maze.WallsProvider;
 
 public class LineColumnModel
@@ -40,6 +41,10 @@ public class LineColumnModel
         return c;
     }
 
+    public short getWalls(Position cell) {
+        return getWalls(cell.getX(),cell.getY());
+    }
+
     @Override
     public short getWalls(int x, int y) {
         return (short) (