He found it 24

The indoor shadows were becoming too familiar, so I crept to the front hallway where the morning draft slips under the door. Near the base of the umbrella stand, a lost chrome key ring lay flat against the parquet floor. I paused. Kept perfectly still to study it. Using one black side limb, I prodded the shiny metal loop upright until it leaned against a wooden shoe horn. When I peered through the circle, the whole hallway looked curved and inverted. A small adjustment, but it changes the view entirely.