Wall planes for rib placement
Stand far enough away that your shirt fabric does not snag on texture. Compare shoulder blade distance to the grout lines without forcing contact.
If paint is delicate, use air gap spacing instead of leaning force.
Chair seat as depth marker
A firm chair offers a horizontal edge to note hip height during partial ranges. Cushions are noted in captions when they change the measurement.
Share a room measurement note
Window light as tempo cue
When daylight moves across the floor, it becomes a passive timer: practice blocks can align with how long a rectangle of light takes to cross a mat border. Descriptions avoid prescribing exact durations.