debugging strategy: use sounds or pictures

I'm still not super satisfied with the examples in this one, I'd love to hear examples of how you use visualizations or sounds to debug

@b0rk I preferred colored backgrounds to border because border could change dimensions in unpredictable ways
@tbaxter that's why it says **outline** and not border -- outline in CSS doesn't change the dimension like border does. maybe it's worth making that more clear though!
@b0rk I definitely jumped to the wrong conclusion
@tbaxter (colored backgrounds are a good idea too though!)