3 ms·

> Flags don’t have dedicated codepoints. Instead, they are two-letter ligatures. (...) There are 258 valid two-letter combinations. Can you find them all? Well

• mercer 6y ago
  Haha, playing around with reversing flags was the first thing I thought about trying.
  • vanderZwan 6y ago
    The surprising result (to me at least) was that out of 270 valid letter combinations, 105 can be reversed. The odd number is easy to explain: letter pairs like MM => MM can add a single flag instead of a pair of two flags, but the fact that almost two out of every five flags are reversible feels pretty high to me.
    • SamBam 6y ago
      > but the fact that almost two out of every five flags are reversible feels pretty high to me. I think some letter-frequency analysis can probably explain it. Given the fact that certain letters are less likely both as the first slot and second (e.g., there are only 4 country codes that start with J, and 3 that end with J), the letters that can be used as both first and second characters are over-represented. It's the same as how far more English language words can be reversed to make other valid words than you would expect if the letters were equally-frequent and arbitrarily arranged.