A friend of a friend posted this on Facebook. I'm totally stumped, but thought he would eventually post the answer, but it turns out he doesn't know either
The question marks are either 0 or 1, but can any of you intelligent people tell me which they are, and why?
Liam Tiernan wrote:How pissed off would you be if I told you it took me about 10 seconds to spot it?
Not pissed off at all, just very impressed. Might be inclined to be a tad peeved if you're being slightly smug (you're probably not) and implying I'm a bit dim (you're probably right)
You've solved the puzzle and then posted your answer in the form of a puzzle that people still have to work out. Was that intentional?
I don't think it was intentional. I think he just found the original puzzle so easy and trivial that he assumed everyone would immediately know that his answer was the numbers 1,2,3,...,15 written in binary.