Use what you now know about LEDs, coordinates, and brightness to create your own project: a screensaver, or a game. You should find a way to use coordinates in your program. Even better, use variables to store and update your coordinates.
## Screensavers
One type of project is a screensaver. A long time ago, computers and televisions used cathode ray tube (CRT)screens for displays. The glass screen of the display was coated on the back with phosphor, a substance that glows when painted with electrons from an electron gun at the other end of the tube. When the same area of the screen was painted (excited) over and over again by the stream of electrons, that part of the screen would sometimes "freeze" with the same image, burned into the phosphor for good. This was called "burn-in".
Normally, if a show was running, or if someone was actively using the computer, the display changed often enough that burn-in wasn’t a problem. Programmers learned to create a demo screen with an animation that would run whenever the screen was idle. Today, nearly all computers and television sets use LCD displays, which are not affected by burn-in. But you can still find a screen saver in nearly every computer's Settings panel, as an opportunity to show off some neat graphics or animation.
* A "screen saver" animation using the plot/unplot blocks. You can fill the screen line by line, pausing between each one, or fill it with a random constellation of stars.
Your project might use variables to store the values of sprites, which are special structures that contain an x and a y coordinate together that describe the sprite's location as one LED on the screen.
This project uses a for loop with the plot/unplot blocks to create a symmetrical design on the screen. This student used a subtraction operation to get a variable that decreases as the index variable in the loop increases.
This project uses a for loop with the plot/unplot blocks to create a symmetrical design on the screen. This student used a subtraction operation to get a variable that decreases as the index variable in the loop increases.
This example creates a diagonal cascading effect across the screen. Note the use of a variable (speed) to allow you to easily change the speed of the animation by changing just one number value.
This is a Dodge Ball game that uses one sprite (dodger) to try to avoid another sprite (ball). You use the A and B buttons to move the dodger to avoid the balls that are falling from the top of the screen.
