In the Shape Editor, you can create a new shape or change an existing shape.

Click the left mouse button to fill a box; click the right mouse button to clear it. Hold a mouse button down and drag the mouse pointer to fill or clear many boxes at once. You can click buttons to flip the shape horizontally or vertically, rotate it (90 degree clockwise at each click), restore the shape originally brought into the shape editor, or clear the shape so you can start a new shape.

When you are finished creating the shape, you can see the turtle at different headings by entering a degree heading in the Sample box. Enter the number of degrees between turtle rotations and choose whether to assign this shape to all active turtles or just the lowest-numbered active turtle. You can also send the shape command to the Listener window by checking that box.