Which Command is Used to Move the Turtle Backward?

In programming environments that utilize turtle graphics, such as Logo, the primary commands used to move the turtle backward are BACK and its shorter form, BK. These commands allow you to precisely control the turtle's movement in the opposite direction of its current heading.

Understanding Turtle Backward Movement

Turtle graphics is an intuitive way to introduce programming concepts, especially for drawing shapes and patterns. The "turtle" is a small cursor on the screen that responds to commands, moving around and drawing lines as it goes. While FORWARD (or FD) moves the turtle in the direction it's facing, BACK (or BK) moves it directly opposite that direction, without changing its orientation.

The BACK Command

The BACK command is straightforward. It takes a numerical argument, which specifies the number of "steps" or "units" the turtle should move backward.

• Syntax: BACK <number_of_steps>
• Example: Typing BACK 10 (followed by pressing Enter) will move the turtle backward by ten steps. You can replace 10 with any desired number to control the distance.

The BK Abbreviation

For convenience and quicker typing, BK serves as an abbreviation for BACK. It functions identically, requiring a numerical argument to specify the distance.

• Syntax: BK <number_of_steps>
• Example: Typing BK 10 (followed by pressing Enter) will also move the turtle backward by ten steps, just as BACK 10 would. This demonstrates that you can change the number of steps after the command.

How to Use Backward Commands Effectively

To execute a backward movement, you typically type the command followed by a space and the desired number of steps, then press Enter.

Here's a quick reference for these essential backward movement commands:

Command	Full Form	Description	Example Usage
BACK	BACK	Moves the turtle backward by the specified number of steps.	BACK 10
BK	BACK	Abbreviation for BACK. Moves the turtle backward by the specified number of steps.	BK 20

It's important to note that moving backward does not change the turtle's heading. If the turtle is facing north, BACK will move it south, but it will still be facing north after the movement. To change the turtle's orientation, commands like RIGHT (or RT) and LEFT (or LT) are used.

For more information on Logo programming and its various commands, you can explore resources such as the Logo Programming Language on Wikipedia.