Several kinds of Sketchpad objects share important characteristics with each other. The most important of these are path objects, straight objects, layered objects, translucent objects, values, plots and sampled objects, and text objects.
Path objects can be used to construct points that stay on the path and as animation paths. You can also measure the position of a point on a path and plot a point at a particular position on a path.
Straight objects include segments, rays, lines, and axes.
Layered objects occupy a two-dimensional area and appear in a layered order when they overlap.
Translucent objects have adjustable opacity to allow objects in layers below them to show through.
Text objects can be aligned with each other.