Instead of working with pixels to create graphic images, Illustrator defines an image as groups of objects defined by outlines. These objects have other characteristics besides shape and size, such as fill color, outline thickness and color, patterns and gradients, etc. A path is a line or curve between two endpoints. The endpoints define the limits of the path. In addition to endpoints, a path may contain other internal points.
Curved paths have at least one anchor point.
An anchor point is an internal point along a curved path that may be used to adjust or reshape the curve. Each anchor point has direction handles and direction points that can be manipulated to adjust the curve's shape. Paths can be open to produce lines and curves or may be closed to form closed figures. Besides the general-purpose pen tool which is used for constructing paths, Illustrator has an array or other drawing tools for creating spirals, lines, brush strokes, regular polygons, and such. Once a path or figure is defined, it can be edited easily by adding or deleting internal points.