The rule could be anything, as funny or as serious as you want. The universe will progress in a similar way that it has up until this point, unless your changed rule prevented it from doing so.

Some examples might be:

  • The invention of currency is not allowed.
  • Iron is slightly less stable.
  • The Ancient Greeks are able to cultivate Silphium, which does not go extinct now.
      • Cataphract@lemmy.ml
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        2 months ago

        maybe it would look like a reverse snowfall underwater if the ice is buoyant? I imagine if the ice stayed at the bottom it would be interesting evolution wise since most things survive the cold by being at the bottom.

      • dream_weasel@sh.itjust.works
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        2 months ago

        Ice fishing is now just called fishing.

        It also becomes much easier to make perfectly clear ice at home: you pour the unfrozen, cloudy water right off the top of any partially frozen thing.