Moving a point: move the cursor over a point. The color will change to show the point is ready. Click down and move the cursor while the mouse button is still depressed. Or use the arrow keys to move the possition of the currently selected point.
Selecting a point: The currently selected point is indicated by "handles" (four dots forming a square around it.) To select a point, move the mouse over it (indicated by a color change) and click. Alternatively, use the TAB key to move from one point to another.
Removing a point: Press the DELETE or BACKSPACE key to delete the currently selected point.
Changing the line: The line is automatically fit to the points. There must be at least two points before a line is drawn. Add/change points to get the correct line. If this does not work, contact your teacher.
Grade: evaluates the current state of the drawing against internal information about what is correct. Depending on settings for the particular exercise, this may give specific information about what is right and wrong.
Reset: returns the applet to its initial condition.