[click on picture to enlarge - NOT taken via iPhone]
In French, when you want to make sure not to forget something, you are advised to "faire un noeud à ton mouchoir" (make a knot in your handkerchief).
In English you make sure to "tie a string around your finger". Which can be painful.
Well not anymore, with this object found for you at the flea market. Now, all you need to remember is... er... why did I tie a string around my finger again?