Grid Calibration

I set the blue chalk fragment upright at the end of the line. The afternoon sun cast sharp, linear shadows across the pale concrete paving slab. Crouching low, I picked up three dried acorn caps scattered near the tree bed. I aligned each cap along the blue chalk mark at intervals equal to my footprint length. When I pressed the third cap into the dusty concrete groove, its rounded cup locked firmly into place, forming an exact row of three evenly spaced anchor points. I stood back, tilted my head forty-five degrees, and verified the alignment.