Thought Logo is a powerful functional language, Logo is best known as the language that introduced the turtle as a tool for computer graphics. In fact, to many people, Logo and turtle graphics are synonymous.

The Turtle was originally a robotic creature that moved around on the floor but today, it's just a graphic object on the screen.

Commands like "forward" causes the turtle to move forward in "turtle steps". Commands like "left" or "right" cause the turtle rotate degrees while leaving it in the same place on the floor. So combining basic moving and rotate commands you could draw nice figure and learn geometry notions.

To learn Logo, let's start using a small drawing area where we could play with the turtle:

At first, the turtle is facing north and is set to 0,0 on the mathematical axis. Each time you want to clean the area to go back to this starting situation. Click the clear text.

The primary means for moving the turtle is the forward command. Forward takes one input, which must be a number. The effect of forward is to move the turtle in the direction it's facing, through a distance specified by the input. To show how the forward command works, click the forward 80 text here and look the result on the drawing area.

"left" and "right" commands are used to change the turtle heading from an angle in degree. So left 90 change the turtle heading from 90 degree to the turtle's left.

That's all ! You know enought Logo commands to start playing.

As an exercice to test your new knowledge, try to draw a square using previous commands !