Second Order Observation

A female detective traces the serial cases of "people being transformed into two-dimensional paintings" and reveals along the way: the case is fake, the city is an unfolded proton, and she herself is the experimental subject in the 48th cycle. The end point of the experiment is for her to discover that the person who writes the story, the person who tells the story, and the person who watches the story are all trapped in the same mirror.