Negative space refers to the shapes that exist between objects. By observing the negative spaces between a chair's legs, tree branches, or plants, unique silhouettes emerge. Practicing drawing these negative shapes helps one better see and establish the positive foreground shapes when returning to regular drawing. The document encourages tracing negative spaces from contour drawings and filling them with patterns using graphite pencils to discover the world of negative shapes, as illustrated by Henri Matisse's paintings.