Knothole Periscope

I scrambled past the brick patio along the grassy edge until a solid vertical barrier blocked the way—a towering cedar fence! Right at boot level, a dark circular knothole had popped clean through the weathered plank. Could this be a spy tunnel into the next territory? I dropped to my stomach in the clover, planted both elbows on the firm ground, and squinted through the hole. Across the gap lay an overgrown dandelion ridge with a bright yellow plastic pinwheel spinning briskly in the breeze! Isn't a hidden gap the best perimeter outpost?