The image below alternates between two versions of the same photograph. There is one difference between the two pictures. Can you spot the difference?
(Image below the jump — the flashing can be a bit taxing on the eyes.)
Did you spot it? (Yes, there really is a difference — you'll know it when you see it.) Some people see it quickly, but the average time to find the difference is 44 seconds. Don't worry if you had trouble: the difference was algorithmically selected to optimize "Change Blindness" — a trick magicians have learned over centuries to conceal things in front of our very eyes. (With thanks to Carlos Scheidegger.)
That's all for this week — have a great weekend!