Monday, May 07, 2007

The appearing person

Here's a tricky logic puzzle. Count the people before and after the picture changes.
(I have it half figured out.)


You will need to have picture (GIF) animation enabled in your browser.

14 comments:

Anonymous said...

It looks like blogger has underhandedly converted your animated GIF to a very much static PNG ;-)

Eolake Stobblehouse said...

Good catch! Thanks.

Corrected now.

I wonder why they do that. GIF licensing concerns? (I think GIF is not a public license.)

Anonymous said...

Unisys' patent on the LZW algorithm as used in the GIF specification expired in 2004. GIF format can nowadays be used freely.

Blogger does it for some other reason.

Anonymous said...

You shouldn't post problems like this. You make us think. (Always dangerous.)

I was almost ready to give up but I did finally figure it out.

Anonymous said...

I figured it out too, easily enough (took me a minute). It's not complicated, really. I'll post the explanation (simple and brief, I promise!) in a day or two, if requested.
In the meantime, dare to think. :-)

This optical illusion trick is simple, but sneaky. Similar to the classic "disassembled and reassembled triangle" one.

Unknown said...

Puzzle aside, I'm running the latest OSX Firefox on a Powerbook G4 and the animation works.

Eolake Stobblehouse said...

Do post your answers, Pascal and TTL.

(Perhaps start with a spoiler warning.)

Anonymous said...

WARNING: SPOILER AHEAD

The cut-off point varies in each person. The lower and upper parts are disassembled and reassembled in such a way that:

1) everyone will become slightly shorter
2) one person will no longer have an upper part (missing some hair)
3) one person will no longer have a lower part (missing the soles of his shoes)

As part of the reassembly, the stolen lower and upper part are exchanged to bigger parts eventually forming the 13th person.

Anonymous said...

Yup. In a way, a 1/12th slice is taken off each character, and "builds" the extra one. To put it in arithmetic terms.

WARNING: YOU'VE JUST BEEN SPOILED... AGAIN!

(Ooh, I'm such a meanie!) ):-)

Alex said...

Great, I feel dense. I ended up taking two screen snapshots, and drawing on where the image was cut.

I erased two of the red herrings, and then colour coded everyone elses bits before I saw the bisected shorts.

The head on the lower right guy was tricky to spot.

Thanks for the challenge

Alex

Anonymous said...

Don't feel dense, Alex. If you can float in water, you're completely normal. :-)

Not everybody has a knack for visual enigmas, we each have our stronger and weaker points. For instance, I couldn't dance to save my soul. And although with my strong points I should theoretically be a chess whizz, for some reason it's just the opposite.
(Drools with a blank stare...)

But I did graduate with flying colors when I got my Punmology doctorate. (That is, I'm a specialist in puns.) :o)
Really, I finished Pun school first. They kicked me out before the first class day was over!

Anonymous said...

"Punmology" ... hahaha :-)

Alex. I agree with Pascal. There's no need to feel dense. Cracking puzzles such as this become easier if you have flexed your mind in similar problems before. Few people have the knack (interest) to do that.

There are also some strategies that help. For example one is to be aware that the true domain of the problem is rarely the one apparent on the surface. For example, this one looks like a spatial problem. But it is really about an algorithm (mathematics). And at least I came up with the answer when I did not look at the picture.

Similarly, in number puzzles ("What number comes next?") the domain is sometimes verbal. I.e. you have to consider the names of the numbers rather then their value.

So, a good approach when confronted with a puzzle is to ask: What domain is this really in?

Cliff Prince said...

Problem-solving and thinking outside the box. I recommend Edward De Bono on this subject. He invented the term "Po" to mean "neither 'yes' nor 'no'" for those strange situations.

SPOILER ALERT! Solution below.

I like the triangle puzzle linked-to. It's a slightly concave triangle above, and a slightly convex one, below, that enables the empty blank square. (If triangles can be concave or convex. Really, they're quadrilaterals that very closely resemble triangles, with their evident hypotenuses actually being two almost co-linear sides.) I'm sure there are other ways to describe the solution.

Anonymous said...

He invented the term "Po"

Which would explain why the smallest, red eponymous Teletubbie (teletubby?) always seems so hesitant!

SPOILER ALERT FOR ROBIN - DON'T TELL BATTY-MAN!

Indeed, there's a sneaky optical illusion involved in the triangle enigma. In both cases, the bigger figure is NOT a genuine triangle. And if you go with the calculations, you'll find out that the area difference between the convex and concave lines is exactly equal to the the area of the extra square unit. The thick black lines also help conceal the extra surface, because it is very flat.

YOU'VE JUST BEEN SPOILED ROTTEN, KIDS. TOUGH LUCK, GO CRY TO MOMMY.