Do you notice how 99 percent of the time in yoga asana practices; we seek to make right angles (90 degrees) in one to many locations in the body? Do you find yourself often cueing your students towards this structure? Just like with buildings, square structure adds stability. A main reason for this is basic physics: when something is slanted, gravity can exert greater force on it. In the body, that means greater muscular force must counteract that force - or one falls to the ground.
In asana practice, we're not looking to exert force for the sake of doing so. We want bones, muscles and joints to work together in an integrated manner. We also want to stay in postures (rather than fall), for at least a few breaths, so that can reap their various benefits. We want to then move, (ideally speaking) with a balance of fluidity and control, to consecutive postures. All of this in mind, to can compare practicing yoga asanas to creating architectural structures with our bodies.
Just like with anything in life, there are exceptions and other limitations to this perspective. The human body is not a building, of course. There are natural curves, such as in the spine, that we want to respect (even if we mindfully decrease them in some postures). Sometimes we're actually looking for rounding (in many arm balances) and arching (in backbends, after a vertical lift of the sternum). Human bodies also aren't made of the same materials as buildings, of course. Muscle and connective tissue can soften (unlike steel and concrete), something we're often trying to have happen in asana practice.
There is always a firm architectural foundation somewhere in yoga postures, however - wide, flat hands and elbows right over wrists in arm balances, and strong feet and legs channeling the earth's energy in backbends. Otherwise, one would fall to the ground! There's even an anchor in seated twists and forward folds. In the former, it's both sitting bones grounded into the earth. In the latter, it's that again, as well as the back(s) of one (or two) leg(s) firmly planted in one's surface. If there weren't a foundation there, one would shift in the posture - and therein not receive the benefits at the intended body areas that the posture can offer. Overall, thinking about asana from an architectural perspective can lead to greater stability - and through that ease - in asana practice.
That established, how could we effectively guide our students to find a strong anchor, a firm foundation, in every posture? I like to key in to this concept with a few particular postures. When setting up in Tabletop to warm up the spine in Cat Cow (which I personally cue in almost every class or private lesson I teach), for instance, I ask students to check in with their stacking of shoulders over wrists and hips over knees.
I also ask them to check that they have elbow creases rolling forward, with triceps spinning back, and even distribution of weight through flat palms and fingers (which are spread wide). That set of muscular actions is crucial for safety of the shoulder girdle and stability in postures from Downward-Facing Dog to more advanced arm balances and inversions. I also reinforce that most of the time in yoga asana practice, we're looking to create right angles in the body - just like with buildings. Half-jokingly, with a little smile, I say, "If I see a slanted building, I'm not about to get in it!"
For standing postures, we can find the stability of rock-solid buildings (or mountains that have not moved for millennia, as the name of the posture implies) in Mountain Pose (Tadasana). We can cue students to align their bodies for optimal stability, structural integrity and space for breath - distributing weight evenly though the feet, rolling the inner thighs back, abdominals slightly in and up, collarbone broad, shoulders relaxed down and across the upper back, and chin parallel to the floor.
We can remind students that if they take a few breaths (or even longer) to really absorb these cues and bring them into muscle memory, they will be able to come back to the same stability and physical integration at any point of their practices. Greater mental harmony, a quieting of the "monkey mind", could very well be a very refreshing result of doing so. Further than that, we can emphasize for our students that if they can come back to this feeling at those times (and ideally learn to maintain it for longer periods of practice, over time), they can come back to it at any point of any day! It sometimes just takes a little time and a bit of mindfulness. The likely results of increased physical ease, yet strength, as well as greater mental clarity and peace, are certainly worth it!