How does this work?

[Saiyaman 0]

Watch this GIF:

As you can count there is 12 people, once they switch over there is 13... Where does the extra person come from?

I opened it up and looked at it frame by frame and didn't find anything, someone else might want to look.

EDIT: No Googling for the answer

[daangelo29 5]

I think I get it. And you can't get it easily by checking it frame by frame. You'll have to do it "piece by piece"...

Just take the bottom half just before the two top parts swap places. Take the two swapping ones, too, separately.

+ +

Try counting them through the bottom half. It's 12, right? Now, try counting them on the top altogether, and it should also be 12.

With the 3 separately taken parts, try put them back together in place manually, but don't connect the two to their bottom parts.

In the frame when they were 12, try counting them part by part. Note that the one above is in the same number as its bottom in each of the sides. Now, swap them.

In this second frame, you'll notice that, obviously, the upper part is two counts lower or higher than the bottom.

Now, focus on the dude with the backward C nose, the one with a red box around him below (ignore the one with the blue box). Notice that the dude only left just a very small piece of his shoes behind in the right part, so when he got to the other side he looked as though he had flat-bottomed shoes. While the rest each had a "slot" in the bottom part to place himself (or herself) in, this dude placed himself in a blank space.

=

This is how the illusion was made -- the backward C nosed dude acted as both the 10th person in the first frame, and the extra 13th person in the second frame.

The main reason why one top part is just sliding to the other side inside of detaching the same way as the other because this way it's hard to spot it without going through all of these, even if you try to check it frame by frame.

I hope you understand my point here. I can't really explain it at my best right now at the moment (too tired and sleepy). If any of you guys who get my point can explain it better, just use the pics I posted.

Sources: MS Paint and my creative head

[EarthwormJim 1]

its easy, just watch the pairs of shoes

[♠Grim♂ Reaper 1666◙ 17]

`for the 13th if you look in the part with twelve there is 3 rows of 2 but in the next one at 13 there is 2 rows of 2 insead

[daangelo29 5]

I already explained about the 13th person in my previous post.