Good example, I'd forgotten about that. On second thought I was mistaken about the example I gave. If someone says You can have tea OR coffee they're really ex

Good example, I'd forgotten about that. On second thought I was mistaken about the example I gave. If someone says You can have tea OR coffee they're really expressing a NAND. You can have at most one out of the two options. Unlike with XOR, you're permitted to have neither. To express XOR, you'd need to say You must have tea or coffee.