Box breathing

Box breathing is a technique used to calm yourself down with a simple 4 second rotation of breathing in, holding your breath, breathing out, holding your breath, and repeating.
Also know as Navy SEAL breathing technique, or tactical breathing, it's a surprisingly simple and effective way to help regain calm and control of your thoughts when under stress.
A perfect visual meditation for when you can't listen to audio, or just need a quick second to refocus.
Use this image to help you keep time! :)
Here are the directions:
Inhale for 4 seconds (as the circle expands)
Hold your lungs full for 4 seconds (as the circle stays fully expanded)
Exhale for 4 seconds (as the circle shrinks)
Hold your lungs empty for 4 seconds (as the circle is contracted)
That's it!

Hmm.  I wonder if SEALs actually use this or if its more nonsense being passed along.  I would think they'd be more interested in controlling breathing so they could dive deeper (they do "free dive" don't they?), not just to "calm down".