> For the complete documentation index, see [llms.txt](https://computational-thinking-in-room11.gitbook.io/room-112-dhs/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://computational-thinking-in-room11.gitbook.io/room-112-dhs/software-development/led-screen.md).

# LED Screen

Each little LED  can be programmed

![There is a 5 x 5 Grid - 5 Across and 5 Down ](https://2507214486-files.gitbook.io/~/files/v0/b/gitbook-legacy-files/o/assets%2F-LpUPSf3tCxHePJxNjfg%2F-M1W9JZy-ycxM75Vzo7E%2F-M1WA7NbUT5DR9lcareU%2Fimage.png?alt=media\&token=d6b15473-3219-4f4b-a237-1d39f6fef20e)

Each LED has a specific X,Y Coordinate but there is ONE problem - the GRID numbers are `0, 1, 2, 3, 4` 

So here is the grid pattern for the LED lights in the checkerboard pattern above

![](https://2507214486-files.gitbook.io/~/files/v0/b/gitbook-legacy-files/o/assets%2F-LpUPSf3tCxHePJxNjfg%2F-M1W9JZy-ycxM75Vzo7E%2F-M1WAVz8U8xQtCEhXdS1%2Fimage.png?alt=media\&token=bc9f94ff-0761-49df-82e9-8655c3b763f8)

The technical term for turning and LED ON or OFF is `plot - the light is  either on or off- there is no dim`

```
On Button A
    plot (2,2)
    //the little middle light should turn on 
```

Now write to code to draw a diagonal line across the LED screen using the plot points 

![No program it and make sure you understand how to use the (X,Y) grid system](https://2507214486-files.gitbook.io/~/files/v0/b/gitbook-legacy-files/o/assets%2F-LpUPSf3tCxHePJxNjfg%2F-M1WCJtKDrDbSUN6yE2G%2F-M1WFPffEvKj--xhys1G%2Fimage.png?alt=media\&token=6a6cbbcb-865c-467c-8d74-38070eec8163)