diff --git a/sketchable.js b/sketchable.js
index 7c5cfde..fcb599a 100644
--- a/sketchable.js
+++ b/sketchable.js
@@ -84,8 +84,6 @@
         timestamp: (new Date).getTime(),
         // Save a pointer to the drawing canvas (jSketch instance).
         sketch: sketch,
-        // Save a pointer to the drawing canvas (jSketch instance).
-        sketchable: this,
         // Save also a pointer to the given options.
         options: options
       };
diff --git a/sketchable.memento.js b/sketchable.memento.js
index 2ad5b8b..8a71110 100644
--- a/sketchable.memento.js
+++ b/sketchable.memento.js
@@ -207,7 +207,7 @@
     }
 
     // Expose public API: all Sketchable instances will have these methods.
-    deepExtend(instance, {
+    deepExtend(Sketchable.prototype, {
       /**
        * Goes back to the previous CANVAS state, if available.
        * @memberof Sketchable