Use the pencil to draw in free hand.
You can change setting to allow you to draw ovals or rectangles, using solid or dotted lines etc.
When you click the pencil-tool the following options appears:
Click an option to get an explanation.
Use pencil mode to force the drawing to be straight lines, curved lines, ovals, rectangles etc.
Use this option to select a color for your drawings.
Choose which line-thickness fits your drawing.
Note: You can even change the thickness of an existing line. Simply click the line to select it, and then enter the desired line-thickness.
Line style is used to control the style of your drawings. You can choose between predefined (solid, dotted etc) or you can choose "custom" to create your own style.