If you look down you may see a crease, a fold or a wrinkle in the carpet for instance. Signifying a movement or activity that happened on the surface of that very floor space. Highlighted as a small furrow, ridge, or crease on a normally smooth surface, caused by crumpling, folding, or shrinking. This usually causes a slight annoyance and is firmly pulled straight. Stumble Upon enhances those folds and curves creating flexibility and contrast.