Yes, for you math experts out there, this is the same basic exercise as the triangle with an added hold of four counts after the exhalation, pausing before taking in your next breath. This further increases the level of oxygen in the lungs and therefore in the bloodstream.
Incidentally, there isn't an endless array of geometrically named exercises - nothing, for example, called "rhombus breathing."
As you begin to become more conscious of your breathing it will filter into your daily life. You will begin to notice when you're not breathing normally and when your breaths are coming in short gasps from the chest or when your mind is racing. You will automatically begin deep belly breathing, which will immediately relax you and calm your mind.
Find out more about this book:Jumpstart Your Metabolism: How To Lose Weight By Changing The Way You Breathe