The purpose of this is to be able to play pong without needing a fancy 2D display. The key here is additional dimensions don't need to be spacial - in this case I chose color.
Future additions, other than code clean up, could include a *3rd* dimension of blink frequency. Need to practice 2D first though!
Demo:
Source code in GitHub: https://github.com/peter-macdonald/linear_pong
Clever use of the Playground Express board, well done!