A middling-length story with a small point. In the seventies and eighties, I helped develop two-dimensional PAGE* image analysis software. Black and white images had a thousand or so spots; the positions of the spots and their size provided information on the characteristics and abundances of proteins in samples. Step one was to get the positions and sizes of spots in a single image. Step two was to compare two images, pairing up the spots. Some spots would only appear in one image and have no pairs; in other cases, two (or more) spots would appear in one image where only one appeared in the other; one spot would be paired with multiple spots. The final step was to consider groups of images. For this purpose, there were groups of spots where (to quote an article on the matter) “each spot in a group is paired with some other spot in the group and no spot in any group is paired with any spot in any other group.” In the mid-eighties, work started on the time zone database. And time zone regions ended up being defined as being places where all the clocks agreed. The small point: the nature of time zone regions has less to do with chronometry or geopolitics than it does with gel analysis. @dashdashado _ * https://www.sciencedirect.com/topics/neuroscience/two-dimensional-gel-electr...