Time for action – animating a radar screen

To pull off a radar pattern, we'll rotate straight lines around a circle, but we'll need to draw upon our earlier work with colors to make the animated effect. Let's create a new stack of blocks by performing the following steps:

1. Let's initialize our starting point with the following blocks:
   • clear
   • go to x: () y: ()
   • set pen shade to (50)
   • pen down
2. Then add a forever block. We want to repeat the following set of blocks:
   • set pen size to (1)
   • turn (90) degrees
   • set pen color to (15)
   • move (60) steps
   • move (60) steps
   • set pen size to (1)
   • set pen color to (101)
   • move (-120) steps
   • turn (1) degrees
3. When you run the script, you should get a pattern similar to the following screenshot. As the pattern repeats, the thin, dark lines create a movement around the center point while the background color remains solid. It's a relatively noisy pattern.
   

   Tip

   To speed up the pattern, use the turbo mode by shift-clicking the green flag.

4. Now let's experiment...