Think you can solve this? It looks simple but the more you look the trickier it gets. I'm planning a post shortly on how to make these types of visual puzzles (and some variations), but thought I should at least post a sample before the spoiler...
The idea is there are three panels - by switching the top two around you get two pictures. The catch is that although the figures line up, there are a different number of people in each of the two resulting pictures. Below is one I made 15 years ago (man!). The first picture has 13 people, the second only 12. For an extra twist, one person has turned into a fresh steamy dog turd. So the question then is, Who turned to doggie doo? Feel free to add spoilers to the comments, but I would recommend trying it once first, it is really pretty freaky. And btw, “the guy in the polka dotted underwear“ gets a loud BZZZT, that is not the correct answer, so please try again : ).
I originally made this one quite a bit wider than it needs to be so it doesn't display that great on a monitor. You can download hi res images (plus the original CorelDraw file) here, if you'd like to print it. Please note: super spoiler post coming in a bit...

These are the three peices of the puzzle - the top two can switch around to make the images below.
Thirteen people, you can count them.

Twelve people, but the dog was busy. So who turned to doggie doo?
PS - Over the years people have asked if they could use this for websites, classrooms, museums, magazines etc - the answer is go for it, do as you please, it is 'public domain'... If you need the files in a different format, please let me know.
***Spoiler alert*** The answer is explained in this post
posted on Saturday, January 14, 2006 4:43 AM