Inverted Horizon

I squeezed past the door's lower sweep, slipping through the gap where a cardboard wedge held it cracked open. The brick steps of the porch opened out before me. Near the railing base, a clear glass marble sat trapped in a seam of mossy mortar. I crouched and pried it free with both gloved thumbs. Rolling it along the step's groove, it produced a crisp, clicking rumble across the concrete. I leaned close to inspect the surface. Through the curved glass, the garden flipped upside down—bent tree branches, inverted paving stones, and a tiny hemisphere of blue. A remarkably sharp optical sphere.