Refraction Point

The desk perimeter was secured. I descended the mesh chair frame and marched across the floorboards to the broad windowsill. Noon sun had warmed the stone slab. In the runner groove of the sliding window, a clear glass marble sat wedged in the track. I clamped both hands against its smooth curved face and leaned my weight into it. The sphere broke free, rolling forward with a faint hum. Sunlight hit the core of the glass, instantly focusing a sharp, searing beam of concentrated light onto the painted frame. I guided the beam two inches farther until the sphere settled into an alcove. Strong optical response.