Shapes are formed by lines that connect to create an enclosed space. The shapes can be geometric (circle, square, hexagon, triangle, etc.) or organic (leafs, flowers, rocks, etc.). Positive shapes are the shapes that are drawn/painted/glued onto the artwork. Negative shapes are the shapes that are created in the space around the positive shapes, I'll get to more examples on that later.
Option 2, Shape Scattegories: Race to see who can draw the most shapes in a minute. You get a point for every shape you draw that no one else drew.