No, it’s a technique where instead of breathing in and out normally, you inhale slowly for five seconds, hold with full lungs for five seconds, exhale slowly for five seconds, then hold with empty lungs for five seconds. Keep repeating, gradually increasing each of the four “sides” of the “box” evenly as you’re comfortable. I usually do it in combination with a mantra, so instead of counting seconds I just say “Om” three times.