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:

• wait number      wait 60
  
  Pause the program during the number of 60^th seconds.
  
  For example, wait 120 will pause the program for two seconds.
• penerase      penerase
  
  When the turtle moves, it erases all it encounters instead of drawing.
• penpaint      penpaint
  
  Returns to classic mode. The turtle draws lines when it moves.

 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!