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.
Comments
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.