diff --git a/projet.use b/projet.use
index 9bdeba3..6ce5242 100644
--- a/projet.use
+++ b/projet.use
@@ -61,7 +61,10 @@ attributes
     type: TypeCase
 operations
     changerEtat(nouveauEtat: TypeCase)  
-    getEtat(): TypeCase 
+    getEtat(): TypeCase
+constraints
+    inv:
+        plateau.cases->select(c: Case | c.x = x and c.y = y)->size() = 1
 end
 
 class Bateau
diff --git a/projet_default.clt b/projet_default.clt
index da40e34..c1e9334 100644
--- a/projet_default.clt
+++ b/projet_default.clt
@@ -208,18 +208,6 @@
                 </strategy>
                 <hidden>false</hidden>
             </edgeproperty>
-            <edgeproperty id="Compose::target::rolename" sizeCalculated="true" type="rolename" userDefined="true" visible="true">
-                <name>plateau</name>
-                <strategy type="org.tzi.use.gui.views.diagrams.elements.positioning.StrategyRelativeToAttached">
-                    <userOffsetX>-21.0</userOffsetX>
-                    <userOffsetY>18.0</userOffsetY>
-                    <attached>Compose::WayPoint::1</attached>
-                    <offset_x>8</offset_x>
-                    <offset_y>8</offset_y>
-                    <placement>TOP</placement>
-                </strategy>
-                <hidden>false</hidden>
-            </edgeproperty>
             <edgeproperty id="Compose::target::multiplicity" sizeCalculated="true" type="multiplicity" userDefined="false" visible="true">
                 <name>1</name>
                 <strategy type="org.tzi.use.gui.views.diagrams.elements.positioning.StrategyRelativeToAttached">
@@ -232,6 +220,18 @@
                 </strategy>
                 <hidden>false</hidden>
             </edgeproperty>
+            <edgeproperty id="Compose::target::rolename" sizeCalculated="true" type="rolename" userDefined="true" visible="true">
+                <name>plateau</name>
+                <strategy type="org.tzi.use.gui.views.diagrams.elements.positioning.StrategyRelativeToAttached">
+                    <userOffsetX>69.0</userOffsetX>
+                    <userOffsetY>-24.0</userOffsetY>
+                    <attached>Compose::WayPoint::1</attached>
+                    <offset_x>8</offset_x>
+                    <offset_y>8</offset_y>
+                    <placement>TOP</placement>
+                </strategy>
+                <hidden>false</hidden>
+            </edgeproperty>
             <edgeproperty id="Compose::source::multiplicity" sizeCalculated="true" type="multiplicity" userDefined="false" visible="true">
                 <name>100</name>
                 <strategy type="org.tzi.use.gui.views.diagrams.elements.positioning.StrategyRelativeToAttached">
@@ -300,18 +300,6 @@
                 </strategy>
                 <hidden>false</hidden>
             </edgeproperty>
-            <edgeproperty id="Etat::target::rolename" sizeCalculated="true" type="rolename" userDefined="true" visible="true">
-                <name>coup</name>
-                <strategy type="org.tzi.use.gui.views.diagrams.elements.positioning.StrategyRelativeToAttached">
-                    <userOffsetX>18.0</userOffsetX>
-                    <userOffsetY>21.0</userOffsetY>
-                    <attached>Etat::WayPoint::1</attached>
-                    <offset_x>8</offset_x>
-                    <offset_y>8</offset_y>
-                    <placement>TOP</placement>
-                </strategy>
-                <hidden>false</hidden>
-            </edgeproperty>
             <edgeproperty id="Etat::target::multiplicity" sizeCalculated="true" type="multiplicity" userDefined="false" visible="true">
                 <name>1</name>
                 <strategy type="org.tzi.use.gui.views.diagrams.elements.positioning.StrategyRelativeToAttached">
@@ -324,6 +312,18 @@
                 </strategy>
                 <hidden>false</hidden>
             </edgeproperty>
+            <edgeproperty id="Etat::target::rolename" sizeCalculated="true" type="rolename" userDefined="true" visible="true">
+                <name>coup</name>
+                <strategy type="org.tzi.use.gui.views.diagrams.elements.positioning.StrategyRelativeToAttached">
+                    <userOffsetX>18.0</userOffsetX>
+                    <userOffsetY>21.0</userOffsetY>
+                    <attached>Etat::WayPoint::1</attached>
+                    <offset_x>8</offset_x>
+                    <offset_y>8</offset_y>
+                    <placement>TOP</placement>
+                </strategy>
+                <hidden>false</hidden>
+            </edgeproperty>
             <edgeproperty id="Etat::source::rolename" sizeCalculated="true" type="rolename" userDefined="true" visible="true">
                 <name>case</name>
                 <strategy type="org.tzi.use.gui.views.diagrams.elements.positioning.StrategyRelativeToAttached">
@@ -392,18 +392,6 @@
                 </strategy>
                 <hidden>false</hidden>
             </edgeproperty>
-            <edgeproperty id="Appartient::target::rolename" sizeCalculated="true" type="rolename" userDefined="true" visible="true">
-                <name>flotte</name>
-                <strategy type="org.tzi.use.gui.views.diagrams.elements.positioning.StrategyRelativeToAttached">
-                    <userOffsetX>105.0</userOffsetX>
-                    <userOffsetY>0.0</userOffsetY>
-                    <attached>Appartient::WayPoint::1</attached>
-                    <offset_x>8</offset_x>
-                    <offset_y>8</offset_y>
-                    <placement>TOP</placement>
-                </strategy>
-                <hidden>false</hidden>
-            </edgeproperty>
             <edgeproperty id="Appartient::target::multiplicity" sizeCalculated="true" type="multiplicity" userDefined="false" visible="true">
                 <name>1</name>
                 <strategy type="org.tzi.use.gui.views.diagrams.elements.positioning.StrategyRelativeToAttached">
@@ -416,6 +404,18 @@
                 </strategy>
                 <hidden>false</hidden>
             </edgeproperty>
+            <edgeproperty id="Appartient::target::rolename" sizeCalculated="true" type="rolename" userDefined="true" visible="true">
+                <name>flotte</name>
+                <strategy type="org.tzi.use.gui.views.diagrams.elements.positioning.StrategyRelativeToAttached">
+                    <userOffsetX>105.0</userOffsetX>
+                    <userOffsetY>0.0</userOffsetY>
+                    <attached>Appartient::WayPoint::1</attached>
+                    <offset_x>8</offset_x>
+                    <offset_y>8</offset_y>
+                    <placement>TOP</placement>
+                </strategy>
+                <hidden>false</hidden>
+            </edgeproperty>
             <edgeproperty id="Appartient::source::rolename" sizeCalculated="true" type="rolename" userDefined="true" visible="true">
                 <name>joueur</name>
                 <strategy type="org.tzi.use.gui.views.diagrams.elements.positioning.StrategyRelativeToAttached">
@@ -508,18 +508,6 @@
                 </strategy>
                 <hidden>false</hidden>
             </edgeproperty>
-            <edgeproperty id="Utilise::source::rolename" sizeCalculated="true" type="rolename" userDefined="true" visible="true">
-                <name>joueur</name>
-                <strategy type="org.tzi.use.gui.views.diagrams.elements.positioning.StrategyRelativeToAttached">
-                    <userOffsetX>-16.0</userOffsetX>
-                    <userOffsetY>-10.0</userOffsetY>
-                    <attached>Utilise::WayPoint::0</attached>
-                    <offset_x>8</offset_x>
-                    <offset_y>8</offset_y>
-                    <placement>TOP</placement>
-                </strategy>
-                <hidden>false</hidden>
-            </edgeproperty>
             <edgeproperty id="Utilise::source::multiplicity" sizeCalculated="true" type="multiplicity" userDefined="false" visible="true">
                 <name>1</name>
                 <strategy type="org.tzi.use.gui.views.diagrams.elements.positioning.StrategyRelativeToAttached">
@@ -532,6 +520,18 @@
                 </strategy>
                 <hidden>false</hidden>
             </edgeproperty>
+            <edgeproperty id="Utilise::source::rolename" sizeCalculated="true" type="rolename" userDefined="true" visible="true">
+                <name>joueur</name>
+                <strategy type="org.tzi.use.gui.views.diagrams.elements.positioning.StrategyRelativeToAttached">
+                    <userOffsetX>-16.0</userOffsetX>
+                    <userOffsetY>-10.0</userOffsetY>
+                    <attached>Utilise::WayPoint::0</attached>
+                    <offset_x>8</offset_x>
+                    <offset_y>8</offset_y>
+                    <placement>TOP</placement>
+                </strategy>
+                <hidden>false</hidden>
+            </edgeproperty>
         </properties>
         <waypoints>
             <edgeproperty id="Utilise::WayPoint::0" sizeCalculated="true" type="WayPoint" userDefined="false" visible="true">
@@ -576,18 +576,6 @@
                 </strategy>
                 <hidden>false</hidden>
             </edgeproperty>
-            <edgeproperty id="Joue2::target::multiplicity" sizeCalculated="true" type="multiplicity" userDefined="false" visible="true">
-                <name>1</name>
-                <strategy type="org.tzi.use.gui.views.diagrams.elements.positioning.StrategyRelativeToAttached">
-                    <userOffsetX>0.0</userOffsetX>
-                    <userOffsetY>0.0</userOffsetY>
-                    <attached>Joue2::WayPoint::3</attached>
-                    <offset_x>8</offset_x>
-                    <offset_y>8</offset_y>
-                    <placement>BOTTOM</placement>
-                </strategy>
-                <hidden>false</hidden>
-            </edgeproperty>
             <edgeproperty id="Joue2::target::rolename" sizeCalculated="true" type="rolename" userDefined="false" visible="true">
                 <name>jeu1</name>
                 <strategy type="org.tzi.use.gui.views.diagrams.elements.positioning.StrategyRelativeToAttached">
@@ -600,6 +588,18 @@
                 </strategy>
                 <hidden>false</hidden>
             </edgeproperty>
+            <edgeproperty id="Joue2::target::multiplicity" sizeCalculated="true" type="multiplicity" userDefined="false" visible="true">
+                <name>1</name>
+                <strategy type="org.tzi.use.gui.views.diagrams.elements.positioning.StrategyRelativeToAttached">
+                    <userOffsetX>0.0</userOffsetX>
+                    <userOffsetY>0.0</userOffsetY>
+                    <attached>Joue2::WayPoint::3</attached>
+                    <offset_x>8</offset_x>
+                    <offset_y>8</offset_y>
+                    <placement>BOTTOM</placement>
+                </strategy>
+                <hidden>false</hidden>
+            </edgeproperty>
             <edgeproperty id="Joue2::source::rolename" sizeCalculated="true" type="rolename" userDefined="true" visible="true">
                 <name>joueur2</name>
                 <strategy type="org.tzi.use.gui.views.diagrams.elements.positioning.StrategyRelativeToAttached">
@@ -688,18 +688,6 @@
                 </strategy>
                 <hidden>false</hidden>
             </edgeproperty>
-            <edgeproperty id="Appartient2::target::rolename" sizeCalculated="true" type="rolename" userDefined="true" visible="true">
-                <name>bateaux</name>
-                <strategy type="org.tzi.use.gui.views.diagrams.elements.positioning.StrategyRelativeToAttached">
-                    <userOffsetX>-4.0</userOffsetX>
-                    <userOffsetY>18.0</userOffsetY>
-                    <attached>Appartient2::WayPoint::1</attached>
-                    <offset_x>8</offset_x>
-                    <offset_y>8</offset_y>
-                    <placement>TOP</placement>
-                </strategy>
-                <hidden>false</hidden>
-            </edgeproperty>
             <edgeproperty id="Appartient2::target::multiplicity" sizeCalculated="true" type="multiplicity" userDefined="false" visible="true">
                 <name>*</name>
                 <strategy type="org.tzi.use.gui.views.diagrams.elements.positioning.StrategyRelativeToAttached">
@@ -712,12 +700,12 @@
                 </strategy>
                 <hidden>false</hidden>
             </edgeproperty>
-            <edgeproperty id="Appartient2::source::rolename" sizeCalculated="true" type="rolename" userDefined="true" visible="true">
-                <name>flotte</name>
+            <edgeproperty id="Appartient2::target::rolename" sizeCalculated="true" type="rolename" userDefined="true" visible="true">
+                <name>bateaux</name>
                 <strategy type="org.tzi.use.gui.views.diagrams.elements.positioning.StrategyRelativeToAttached">
-                    <userOffsetX>24.0</userOffsetX>
-                    <userOffsetY>30.0</userOffsetY>
-                    <attached>Appartient2::WayPoint::0</attached>
+                    <userOffsetX>-4.0</userOffsetX>
+                    <userOffsetY>18.0</userOffsetY>
+                    <attached>Appartient2::WayPoint::1</attached>
                     <offset_x>8</offset_x>
                     <offset_y>8</offset_y>
                     <placement>TOP</placement>
@@ -736,6 +724,18 @@
                 </strategy>
                 <hidden>false</hidden>
             </edgeproperty>
+            <edgeproperty id="Appartient2::source::rolename" sizeCalculated="true" type="rolename" userDefined="true" visible="true">
+                <name>flotte</name>
+                <strategy type="org.tzi.use.gui.views.diagrams.elements.positioning.StrategyRelativeToAttached">
+                    <userOffsetX>24.0</userOffsetX>
+                    <userOffsetY>30.0</userOffsetY>
+                    <attached>Appartient2::WayPoint::0</attached>
+                    <offset_x>8</offset_x>
+                    <offset_y>8</offset_y>
+                    <placement>TOP</placement>
+                </strategy>
+                <hidden>false</hidden>
+            </edgeproperty>
         </properties>
         <waypoints>
             <edgeproperty id="Appartient2::WayPoint::0" sizeCalculated="true" type="WayPoint" userDefined="false" visible="true">
@@ -804,18 +804,6 @@
                 </strategy>
                 <hidden>false</hidden>
             </edgeproperty>
-            <edgeproperty id="Joue1::source::multiplicity" sizeCalculated="true" type="multiplicity" userDefined="false" visible="true">
-                <name>1</name>
-                <strategy type="org.tzi.use.gui.views.diagrams.elements.positioning.StrategyRelativeToAttached">
-                    <userOffsetX>0.0</userOffsetX>
-                    <userOffsetY>0.0</userOffsetY>
-                    <attached>Joue1::WayPoint::0</attached>
-                    <offset_x>8</offset_x>
-                    <offset_y>8</offset_y>
-                    <placement>BOTTOM</placement>
-                </strategy>
-                <hidden>false</hidden>
-            </edgeproperty>
             <edgeproperty id="Joue1::source::rolename" sizeCalculated="true" type="rolename" userDefined="false" visible="true">
                 <name>joueur1</name>
                 <strategy type="org.tzi.use.gui.views.diagrams.elements.positioning.StrategyRelativeToAttached">
@@ -828,6 +816,18 @@
                 </strategy>
                 <hidden>false</hidden>
             </edgeproperty>
+            <edgeproperty id="Joue1::source::multiplicity" sizeCalculated="true" type="multiplicity" userDefined="false" visible="true">
+                <name>1</name>
+                <strategy type="org.tzi.use.gui.views.diagrams.elements.positioning.StrategyRelativeToAttached">
+                    <userOffsetX>0.0</userOffsetX>
+                    <userOffsetY>0.0</userOffsetY>
+                    <attached>Joue1::WayPoint::0</attached>
+                    <offset_x>8</offset_x>
+                    <offset_y>8</offset_y>
+                    <placement>BOTTOM</placement>
+                </strategy>
+                <hidden>false</hidden>
+            </edgeproperty>
         </properties>
         <waypoints>
             <edgeproperty id="Joue1::WayPoint::0" sizeCalculated="true" type="WayPoint" userDefined="false" visible="true">