Rhythm - Rhythm is movement, thus it sets the speed as well as the direction and kind of activity expressed in the flower arrangement. Transition, variation, contrast - each may be important in expressing certain themes. Most expressive arrangements must have dominance well developed. Line - Strong vertical lines may have spiritual connotations. Curved lines may express joy.
Diagonal lines express restless movement.
The form of the entire arrangement is expressive. Low, horizontal arrangements seem calm. Vertical arrangements may express alertness or aspiration. Space - Open spaces ask the viewer to look through them and contemplate. Some flowers are considered more formal than others.