diff --git a/code/selecteur.js b/code/selecteur.js
index 868dbe2..2d23a4a 100644
--- a/code/selecteur.js
+++ b/code/selecteur.js
@@ -38,4 +38,5 @@ else if(get['mode']=="surv")
     document.getElementById("chronotime").style.display="none";
 }
 
-diff=get["diff"];
\ No newline at end of file
+difficulty=get["diff"];
+console.log("difficulté = "+difficulty+" mode:"+get['mode']);
\ No newline at end of file
diff --git a/code/vitraux.js b/code/vitraux.js
index 6d89f84..381758a 100644
--- a/code/vitraux.js
+++ b/code/vitraux.js
@@ -231,9 +231,12 @@ var canvasT = document.getElementById('canvasTotal');
                     element[0]=-element[0];
                 })
             }
-            
-            toutDessiner(letab,lecanvas,lectx);
-            empiler();
+            if(lecanvas!=null)
+            {
+
+                toutDessiner(letab,lecanvas,lectx);
+                empiler();
+            }
         }
         
         function getRandomInt(max) { //rng entier [1;max]
@@ -253,29 +256,52 @@ var canvasT = document.getElementById('canvasTotal');
             tabObj=[copyMDArray(tab1),copyMDArray(tab2),copyMDArray(tab3),copyMDArray(tab4)];
             tabObjCmp=[];
             var actions=getRandomInt(4)+1;
-            var swapTreshold=10;
-            var switchTreshold=10;;
-            if(diff=="med") //70% tournerD, 30% swap
+            var swapTreshold=11;
+            var switchTreshold=11;
+            if(difficulty=="med") //70% tournerD, 30% swap
                 {
                     actions+=getRandomInt(3)+3;
                     swapTreshold=8;
                 }
-            if(diff=="hard") //50% tournerD, 30% swap, 20% switch
+            if(difficulty=="hard") //50% tournerD, 30% swap, 20% switch
                 {
                     actions+=getRandomInt(5)+5;
                     swapTreshold=6;
                     switchTreshold=9;
                 }
+
+                console.log("actions : "+actions+" difficulty="+difficulty);
             
             while(actions>0){
-                if(diff!="easy")
+                if(difficulty!="easy")
                     act=getRandomInt(10);
                 else
                     act=1;
-
-                //if(switchTreshold<act<10) // faire un switch
-                tourneD(tabObj,canvasO,ctxO,getRandomInt(4)-1);
-                actions--;
+                console.log("act="+act+" left:"+actions);
+                if(switchTreshold<=act && actions>3) // faire un switch
+                {
+                    var from=getRandomInt(4)-1;
+                    var to=getRandomInt(4)-1;
+                    while(from==to)
+                        to=getRandomInt(4)-1;
+                    
+                    [tabObj[from],tabObj[to]]=[tabObj[to],tabObj[from]];
+                    console.log("switch "+from+"->"+to);
+                    actions-=3;
+                }
+                else if(swapTreshold<=act && actions>2)
+                {
+                    var from=getRandomInt(4)-1;
+                    var dir=getRandomInt(2)==1 ? "H":"V";
+                    swap(tabObj[from],null,ctxO,dir);
+                    console.log("swap"+dir+" de "+from);
+                    actions-=2;
+                }
+                else
+                {
+                    tourneD(tabObj,canvasO,ctxO,getRandomInt(4)-1);
+                    actions-=1;
+                }
             }
             empiler(true);
             toutDessiner(tabObjCmp,canvasO,ctxO);
@@ -327,8 +353,6 @@ var canvasT = document.getElementById('canvasTotal');
                 else
                     break;
             }
-
-            console.log("firstAv="+firstAv);
             
             if(mouseOnRes && !canvasNumber.includes("R")) //clic dans la réserve, relâche sur la pile en jeu
             {