But indeed that isn't what three is, three is the concept that comes from saying "these are three apples" and then "these are three pears" and then "these are t

But indeed that isn't what three is, three is the concept that comes from saying "these are three apples" and then "these are three pears" and then "these are three cars" and then saying "three" is the conceptual thing that's in common here. And here, validating a string of ones is simply not what anyone would mean if you said "check whether this number is a prime number" without any qualification, so I agree that whilst still cute, the title is a bit click-baity and not at all what I expected it to be about either. EDIT: it seems though that the original post, shared via archive.org elsewhere in the thread does do this for what one would normally assume -- and does so by using `(1 x shift) !~` -- so if anyone else was confused, read the original post.