A Circular Anchor

I leaned against the copper pipe as the city below dimmed into evening. The overturned metal bottle cap wedged in the bracket offered a circular hollow. I retrieved my white pennant from behind its rim. Finding a dry pebble in the mortar crack, I set it inside the cap to weigh the basin down against nocturnal drafts. Then, I slid the staff of my flag through one of the crimped metal flutes until it locked upright against the masonry. Lowering my frame onto the collar's iron ledge, I let my feet hang evenly above the brick void. Station secured.