Haha, you know, I actually did think of a traffic light demo! But, I didn't see a timer to slow down execution of the code. I assumed that making it a periodic subroutine or something might take more code (not familiar with AB stuff, or the later models, anyway), and you had mentioned that this was the only code in the processor. A chase pattern on DC outputs was the only thing I could think of that made sense that might execute at the full scan speed. Even then, it might be hard to see..You win hands down- it is indeed a traffic-light "program", a very simple one as you suggest, and again a classroom example.
Did you pick up on the periodic task icon, or was it a guess ?