2. Controlling the Turtle and Pen
Imagine that Logo's turtle, the one we have gotten to know in the past lesson, is holding a pen in his hand while he's walking. He is using the pen to draw a line of his movement whenever he receives a command such as to go forward. Ask the turtle to go 30 points forward and watch the line he draws.
If you don't remember how to move the turtle forward, please return to the first lesson and review it.
We can ask the turtle to lift his pen off the drawing board. Once the turtle lifts his pen, he will no longer draw a line as he walks. The command for lifting the pen is penup Ask the turtle to lift the pen
While the pen is up, moving the turtle will not create any new lines. Ask the turtle to go forward 40 points
You have now seen that the turtle moved forward without drawing any new lines. In order to continue drawing we should command the turtle to put the pen back down on the drawing board using the command pendown Ask the turtle to put the pen down
Now the pen has returned to its previous position, down on the board. We can check that it is ready for action. Ask the turtle to go 40 points forward
Sometimes you can ask the turtle to hide. This way you could see how the drawing you've made looks without the turtle. The command for the turtle to hide is hideturtle Ask the turtle to hide
A hidden turtle can draw just as well when he is hidden. The turtle is shown on the screen only ,so that drawing will be comfortable for you. Ask the turtle to turn left in a 90 degree angle and then go forward 40 points
lt 90 fd 40
Even though you can always work without seeing the turtle, most of the time it's easier to draw when you do see him. When we want the turtle to show up again we use the command showturtle Make the turtle reappear