Cut a small square from the address side of E1. 2. Cut out all the address side from E2 as shown. 3. Stick a piece of tin foil onto E2 as shown. 4. Turn E2 over and glue carefully onto E1, the tin foil corner remaining unstuck. 5. With a card face down in the envelope, the right thumb only has to bend down the loose corner slightly to peek the corner index of the card This envelope is based on an old idea which enables you to secretly discover the name of a selected card slipped inside it.