• Kazumara@discuss.tchncs.de
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      3 hours ago

      Leap years are each fourth year, except each hundredth year, except each thousandth fourhundredth year.

      1896 leap year
      1900 not leap year
      1904 leap year

      1996 leap year
      2000 leap year
      2004 leap year

      2096 leap year
      2100 not leap year
      2104 leap year

      Then you just arrange the 10 year window in different positions to overlap 1 to 3 leap years to reveal the three outcomes of the bug.

      - / - - - / - - - /
      - - / - - - / - - -
      - - 0 - - - / - - -

      - is a normal year, / is a leap year, 0 is an exceptional non-leap year.

      • sexybenfranklin@ttrpg.network
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        11 hours ago

        Small correction, it’s every fourth year except every hundreth year except every 400th year. I’m assuming the misconception comes from the last time it was a 100th also being a 1000th (2000) but the next time a leap year will end in 00 is 2400

        • Kazumara@discuss.tchncs.de
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          3 hours ago

          Ahh right! Thanks for correcting me. Now that you mention it I remember too. It also makes sense, a year is roughly 365.2425 days long. Add 0.25 (one out of four), subtract 0.01 (one out of hundred), add another 0.0025 (2.5 out of thousand which is 1 out of 400)