Optical art
 
Abstract devises which give the appearance of movement or create a vibration as in a moiré, or a sense of depth.

Ogee

 2 mirrored curves forming an onion shape.

Ombre

 An effect like a shadow swelling from light to dark and back often by having stripes which pass from open to closed and reverse.

Ornament

Pattern or decoration , an additional device which decorates a motif.