1. Shape and Form

2. Shape - A two dimensional area with recognizable boundary
Pablo Picasso, Three Musicians, 1921

3. Form - A three-dimensional shape that has height, width and depth

4. Figure - A shape that appears to be on top of background shapes, also called a positive shape

5. Ground - A shape that seems to be underneath or surrounding a figure, also referred to as a negative shape
M.C. Escher, Circle Limit IV, 1960

6. Foreshortening - A method of making an object seem to recede in space and appear three-dimensional by shortening the depth dimension
Andrea Mantegna, Dead Christ, c. 1490

7. Organic - shapes and forms that are irregular, such as those often found in nature: leaves, stones, clouds

8. Geometric - shapes and forms that are usually found in things made by people, such as buildings, bridges, and office machines
Edward Hopper, House by the Railroad, 1925

9. Closed - shapes and forms that seem solid and heavy
Isamu Noguchi, Great Rock of Inner Seeking, 1974

10. Open - shapes and forms that have space around and between them
Kano Sansetsu, The Old Plum, c. 1645

11. Shape Constancy - the tendency to see a shape as unchanging regardless of the angle at which you see it

12. Size Constancy - the tendency to see a object’s size as unchanging no matter how close or far away it is
Camille Jacob Pissarro, The Boulevard Montmarte on a Winter Morning, 1897