Fashion Optical Illusion: horizontal lines broaden and draw attention to whatever area they are on. Also horizontals at the shoulders and hems are more elongating, and make people look taller than horizontals elsewhere.
Fashion Optical Illusion & Vertical Lines: the placement of the vertical lines is also important. The closer they are spaced together, the slimmer you will look. These two shapes are exactly the same size, yet the box on the right looks thinner.