When a tool is selected, options may appear in the area below the bottom of the tool buttons. These options provide a way to customize the tool that you chose. The first illustration at the left shows that the "Line" tool has 5 different widths. The second illustration shows that the "Brush" tool has 12 different shapes, and the third illustration shows that the "Rectangle" tool has 3 variations. The Rectangle, Circle, and Polygon tools can be used in conjunction with the Color Selector to produce a wide variety of shapes, both hollow and filled. Be sure to explore all the possibilities.