Active feet,” Ms. Mather said. We flexed our feet, Barbie doll style. We inhaled, pressed down lower backs, held our breath, lifted tailbones, squeezed blocks. The squeeze lasted through eternity. We exhaled, lifted heads, then shoulders. We kept squeezing. Legs were quivering; minds were shrieking, “Get me out of here!” Inhale. Head down. Repeat.