I was just checking you didn't think this was one of those 'jesus on a piece of toast) things.
Well the optical illusion is seeing just a wall. I think it's really clever, I just didn't see the wall.
The suggestion was fine too? Could be ash? This isn't an optical illusion, it really is a cigar. They stuck a cigar in the wall, and took a photo of it.
Well I never saw the gap/crack, but I think most people just see a wall of bricks with dodgy pointing. So if you didn't see a gap/crack, what did you see between those bricks?
This one I understand better, if people don't see the straight lines of the cigar, then I guess it's easy to miss. The...
************ SPOILER ALERT ************
That snake head thing (or little stone) is the ash end of a cigar. The cigar is sticking out of the wall. Look at the lines to the right of the ash, they're straight, because the cigar is straight. What you think is a gap in the wall is actually a cigar.