repeat allows us to execute any set of commands n amount of times back-to-back. repeat is especially useful when drawing geometric shapes in conjunction with the pen-down and pen-up primitives. For example, if we wanted our turtles to draw a square, we would write the following code:

ask turtles [
    pen-down
    repeat 4 [
        right 90
        forward 5
    ]
    pen-up
]

In the model example below, we have 36 turtles who are initially placed in a circle layout when the setup button is clicked. When we click the go button, each turtle turns right 1 degree and moves forward 0.03 units 360 times. This simple repetition behavior results in a very interesting shape.