WindPlot provides 10 default icons for marks. These icons can be altered by the user by means of a mark symbol editor as shown in this picture. The user types in a series of steps in the direction of the arrows; as he types he sees the icon being formed. Each step causes a black mark to appear in the direction of the arrows. A full series of these steps form a macro that makes the icon. The program provides 50 premade mark macros to choose from or you can create your own.