This is a nice effect to use in combination with a Change Bag routine whereby green and blue hankercheifs are placed into an empty change bag. After a magic pass the hanks are taken out of the bag and shown to have been magically tied together at one corner. The magician can then comment that green and blue don't seem to match very well. When the hanks are then passed through the magician's fist, one hank changes to yellow. Hands may then be shown empty. The joined hanks can also simply be pulled from the magician's pocket or picked up from a table before magically changing color.