The foundation of the canvas is a large piece of fabric known as &quot;hair canvas&quot; that is cut to the shape of the front and then various locations are slashed and either pulled together or spread apart to provide the shaping.    The pieces A, B and C are stitched in front or behind the slits to hold them in the forced positions. A spreads the shoulder edge to provide the beautiful curve to the shoulder. B and C shape the chest and pinch the waist.