The punctuation for the phrase and/or. i may not be the first to come up with it, but i did invent it independently.
This punctuation is the combination of the && and || logical operators in C, Perl, and some other programming languages. It isn't needed as a logical operator in itself, the only reason it's required in English is that the word 'or' is treated as logical xor. So, it's more or less ((A XOR B) XOR (A AND B)), equivalent to logical OR.