When a ruler ran away

I walked from under the chair toward the glass balcony door. The afternoon light fell wide and warm across the floorboards. Lying flat on the wood was a clear acrylic drafting triangle, cool and smooth beneath my fingers. Beside it rested a tiny brass screw from an old spectacles frame. I paused for a long while, watching how the sunlight split across the beveled plastic edge. With both hands, I nudged the tiny screw forward until its round, slotted head braced neatly against the inner corner of the triangle. It caught a thin beam of clear light, casting a slender golden spark onto the floor.