9.1 With drawing area.

9.1.1 First example:

 to ex1
 rt 1
 ex1
 end

This procedure is recursive because the procedure ex1 is called on the last line. While executing, we can see that the turtle turns on itself forever. To break the program, we must click on the STOP button.

9.1.2 Second example:

Here are three new primitives:

 to ex2
 fd 200 penerase wait 60
 bk 200 penpaint rt 6
 ex2
 end

Now, we can execute the program. On each second, the same procedure is repeated. We obtain the seconds of a clock!