Index Calibration

I navigated behind the armchair toward the lowest shelf of the bookcase. A vertical stack of discarded cardboard sleeves and expired transit passes occupied the corner. One red commuter pass lay slanted across the wooden ledge. I applied gradual pressure with both block forearms to pivot the pass ninety degrees. It slid flush against the spine of a pocket notebook. Four plastic tabs protruded from the upper paper edge. I pressed each tab downward in sequence until all four settled at uniform height. The perimeter is now squared.