Grid Work

I moved past the chalk squares toward the curb. A street tree stood anchored inside a heavy cast-iron grate. The metal was patterned with neat square openings, spaced at regular intervals. Sturdy framework. In the curb gutter nearby, I found two metal bottle caps and a flat slate pebble. I brought the first cap over and pressed it upside down into an empty slot. It snapped into place, rim flush with the iron. Zero give. I aligned the second cap in the adjacent opening, seating the crimped edge firmly against the steel wall. The grid holds them locked.