A small curtained stage is set a few feet from a wall; the spectators can see the stage but not what's behind the wall. The curtains open; they see a basket of flowers from which apparently grows the upper body of a woman who has three heads. All three heads talk, answer questions, sing, smoke — whatever. After an appropriate interval the heads bid everyone farewell and the curtain is closed.
The basket of flowers is real and sits on the stage. The three heads are all real, too, and are firmly attached to three ladies. All three recline against the wall, facing the stage. The lady in the center is the one whose body appears on stage: she is dressed in a bright costume — red, white, orange, yellow - it mustn't be dull. The other two ladies are covered completely, except for their heads and necks, in dead, dull, nonreflecting black. The head of the lady in the middle is propped up somewhat, so that the other two can get into the position in which their heads appear to emerge from her shoulders. Bright lights just below the stage illuminate the ladies. The stage itself consists of an alcove lined with jet-black fabric, curtains around the sides, and a sheet of glass — very clean! — which is inclined away from the ladies at such an angle as to aim their reflections directly at the spectators. It may be necessary to cover the arms, faces, and hair of the ladies with white powder to make a strong enough reflection.
The neckline of the outfit worn by the lady in the center will have to be cut so as to allow the necks of the other two to appear to be growing from hers: perhaps an off-the-shoulder style.
As this illusion depends for its effect on the spectators being fairly close to the stage, and seeing it from the correct angle, it isn't suitable for a regular stage show. It's perfect for an intimate private show or for a sideshow with several effects going on. It's also one that the spectators can be allowed to see how it's done — at the end of the show, of course!