A Measure of Gravity

I set down my sword to test an unfamiliar fulcrum. On the corner of the low wooden table stood a metal hex nut and a forgotten wooden toothpick. After aligning my stance, I placed the toothpick across the nut's narrow rim. It tilted, losing contact twice. I paused, adjusted the angle of my right hand, and eased the toothpick until both ends hovered in perfect equilibrium. The symmetry held. I withdrew my fingers, observing the stillness.