Finding Equilibrium

I set a heavy steel hex nut upright on its flat edge in the center of the pine bench. Across its top facet, I laid my wooden toothpick, letting both ends hover above the wood. I placed my stray coin onto the left tip. The slender beam dropped instantly, tapping the wood with a sharp click. Reaching into the open tray nearby, I retrieved a small brass washer and slid it onto the opposite arm. Shifting the ring millimeter by millimeter toward the outer edge, the beam leveled, lifted free of the plank, and hovered dead-horizontal. Both suspended weights swayed gently on the steel fulcrum before resting in still balance.