Remember the lightbar that Google put on the Chromebook Pixel just because it is cool? François Beaufort created an app to control those lights.
LightBar, the new Chrome app works only on Pixel though. The HP Chromebook 11 has a similar looking lightbar, but the hardware inside is different, or limited.
Oh, you also need developer mode on the Pixel for this to work.
If you fit into those categories, install the app from here and start playing with your lightbar sequence.