I love this brief and simple prāṇāyāma (breathwork) practice. Samavṛtti (समवृत्ति) means “same movement,” “equanimity,” or “equable” in Sanskrit.
Count your inhale and your exhale, 4 or 5 or 6 counts each, maybe less or maybe more, whatever count feels like you're breathing without strain. Aim to bring your inhale and exhale into balanced length with one another. Extend the pauses in between your breaths by a count or two. If you can continue on without strain, you might lengthen your breath count by another beat or two. Feel into the spaciousness of the pauses between your inhale and exhale. What do you find there?
To finish, come back to a free breath and notice how you feel, compared to how you felt when you started. For me, this simple technique (and a supported backbend as I demonstrate) are always a welcome reset in the middle of my day, or a calming mini practice at night before bed.