A Circular Transit

I stepped down from the interior sill into the open space near the bookcase base. On the floor lay a forgotten brass key ring and a solitary glass marble. Standing still, I calculated the friction of the dark parquet. I sheathed my sword across my back, knelt on one knee, and set the hollow brass circle upright on its narrow edge. With my free hand, I introduced the marble behind it. A light tap of my index finger sent the sphere rolling forward. It passed cleanly through the upright brass aperture without grazing either inner curve, stopping two paces ahead. The frame held motionless.