In the previous lesson we learned how to use the Linkbot to trace a square. To do so, we used the code blocks shown below.

Note that we used the same  driveDistance  and  turn  commands four times in a row. That is, we instructed the Linkbot to drive 18 units, then turn right 90 degrees, then drive 18 units, then turn right 90 degrees, and so on for the third and fourth sides. In programming we often encounter situations like this, where we need to repeat the same code several times in a row (or even hundreds or thousands of times in a row). Instead of writing (or copying and pasting) the same commands over and over, we can use what's known as a "loop." For a basic loop, we put the commands we want to have repeated inside a special loop code block, and then specify how many times we want the commands to be repeated. This is known as a "repeat loop." (As you continue to learn about programming, you will come across other types of loops as well.) In this lesson you will get to experiment with a repeat loop to have the Linkbot traverse the square.