Studying the Spec Logo user interface

The interface has two panes: the left pane is the drawing pane, which is where the output from the Logo script appears. On the right side is a prompt where the user can edit instructions:

Figure 14.1: The Spec Logo interface

Look at the screenshot. You can see the following:

• The script name in the top-left corner. This is a text field that the user can click on to change the name of the current script.
• The display, which shows script output on the left-hand side of the page. You can see a shape has been drawn here, which is the result of the Logo statements entered at the prompt.
• The turtle, shown in the middle of the screen. This is a little green triangle that marks where drawing commands originate. The turtle has an x and y position, starting at 0,0, which is the middle of the screen. The viewable drawing is 600x600 in size, and the turtle can move throughout this area. The turtle also has an angle, initially...