A Rolling Pebble

A smooth, gray pebble was resting just past the sliding glass door. Sss... I slipped over the metal track and stepped out onto the open balcony. The concrete tiles felt rough and cool beneath my feet. Leaning forward, I nudged the little stone with my front foot. *Clack.* It skittered along the groove in the floor until it bumped against a clay flowerpot. I froze, listening as the faint scrape faded away... then hurried forward to tap it back. It makes a crisp, hollow click every time it rolls.