A shape is a two-dimensional area, whose boundaries can be measured in height and width. A mass, or form, by contrast, is a solid that occupies a three-dimensional volume. How does Ellsworth Kelly work with shapes in Three Panels: Orange, Dark Gray, Green? What are negative shapes and positive shapes? What is figure-ground reversal? Negative spaces are empty spaces that acquire a sense of volume and form by means of the outline or frame that surrounds them. Negative spaces can be used to suggest forms. How does the sculptor of the feast-making spoon (wunkirmian) use negative space to suggest form? How does Barbara Hepworth treat negative spaces in her sculpture Two Figures?