Perimeter Beacon

I advanced three paces past the vertical golf tee marker to inspect the mossy flagstone boundary. Resting in the seam was a clear glass marble and a dried twig fork. Maintaining a steady two-handed grip on my carbine, I pushed the marble forward with my rifle butt until it seated securely inside the timber cleft. Midday illumination struck the curved glass sphere, refracting a concentrated white dot directly onto the dark garden earth ahead. Forward range marker calibrated.