Condensation on the shower door
Standing in the shower, waiting to dry, I exhaled. A blotch of condensation appeared on the glass door. It spread out in all directions like an expanding island in the otherwise clear glass ocean. The edges were uneven like a coastline.
There was a brief pause, as my out-breath ended and the island of fog achieved its maximal mass, then I inhaled and the island started to shrink. Just as the blotch had shriveled down almost to the point of disappearing, I exhaled and it started to grow again.