The Step Edge

I slipped through the open apartment doorway into the quiet corridor. The cool grey concrete of the stairwell offered firm traction. Ahead, the edge of the first descending step dropped off in a sharp, geometric line. At the corner of the landing, a discarded yellow plastic pencil sharpener lay tilted upside down against the painted metal baluster. I advanced three measured paces, locking my leg joints at each step to test stability. Anchoring my hind paws on the solid concrete, I lowered my snout and nudged the sharpener's flat base. It slid two inches until its straight edge rested perfectly flush against the vertical steel riser. Neat alignment achieved. I sat back on the landing, surveying the clean horizontal seam.