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# 2012-11-17: Puzzle - First to solve wins

For years I've had an idea in my head about a way to hide some information in a bunch of numbers. I actually got around to coding an implementation and figured I'd run a competition. The first person who figures out what the famous landmark is described by the second set of numbers below and posts the correct answer in the comments wins $100.

## The hint

Here's a hint. The following numbers are a reference to the Eiffel tower:

8013000130

2411131214

2215221358

9946994669

9353891213

2202091314

7094401130

1847634318

0924799659

5551931884

5045911172

5161967518

5541941447

5021912900

3165335375

7121222222

0546334345

5551651555

5825828545

4243748287

4499499044

2390132901

9336639245

0959128984

9638335921

5996099944

4266142088

5895292259

5447647454

9216516591

0487378031

5485346911

0466261755

5451286455

9217249887

5867305521

5149595151

6955855905

5045455000

4894994999

6944987554

5854565209

7155463415

5149556538

6045570787

1138518118

8808280888

2358998925

6284111198

6828941566

2288504014

1831099269

8831018971

8111542734

2789805757

1774808652

2754331433

6436522984

2256556522

4534143533

1089888918

5476356339

6754554757

0448141044

6230323312

5289222929

9612711627

7415781635

5655193114

5482192016

9239827908

6435262491

8339516261

0913714431

0982826935

6768412470

8126116732

3263202263

3790974930

5292222591

4299729476

9253597597

6351223002

9353241623

2152586145

9291992959

4536225525

2159511959

2052222222

6323553633

4268224618

4874546785

4565492514

8448398434

5471635718

0170622414

4417790634

7942226738

7856496434

7278128871

1732277312

7968776869

8859198898

1638105700

7069258271

7932158227

8856184733

7269220284

7781497669

0314734643

0865301550

2751349997

7765355777

2362826262

7886776787

0254344251

7601406667

4318005992

6479709995

5889448422

0701214932

9411914192

7797997979

0288308832

9353905993

2593429425

## The puzzle

Given the above hint, what famous landmark do the numbers below refer to?

2131509623

6489512088

2880206677

8157524271

2889595858

9747077847

8932739932

6131216632

8650558565

7735060788

3730488904

1865477228

5755189606

3833333338

7752175777

2365456436

8730477008

5822005722

6933352405

4758910282

4472532482

2050032383

2282330282

1199819081

8224342483

5932352332

0840080104

2520520654

8883746719

3829398365

9126746677

8689998959

3773777373

4820348420

2155757551

9476574765

7449753367

1871978861

8023177987

6100673948

7784758847

7777777377

5001113970

5584454958

1886878561

6717449747

7616361167

6775665776

5972975995

7776982554

6716314086

6696504984

7812612910

6817586318

4900940927

3262446832

2272227895

9090915094

5506616824

1776740897

7237845497

6332326090

1455616295

6408990765

0478334555

6338377907

6339981903

6619313639

0499440099

6316066166

0438338300

6479943977

3899944148

4257013397

7372630182

5101839097

4771334147

7919747192

5415813588

9349939349

5522858052

7474944779

3458585130

3525937925

1169551699

9792055990

0534141990

0077889199

0961357778

8177481379

2239227493

2249449248

5153335317

3559554583

2618037247

1318026493

4850353247

4890574218

9164624387

2537517323

1483392904

0384508561

1464304911

0484334040

1373533337

2111411641

3534543454

0267882222

3476920656

0616979515

3746990431

6476584376

4564151544

0746904809

3676997763

9408884808

6716577511

6338363633

2478688276

0294794948

5548354554

5298381109

6508326640

6548330881

2208781487

6528779134

Post the answer as a comment below. ~~The first person to answer correctly with an acceptable explanation to how the answer was reached (rather than just a guess) wins $100, so make sure to use your correct e-mail address so I can contact you.~~

**Note #1:** People have noted that the numbers change whenever the page is reloaded. That's as expected. This puzzle is *not* an *encryption* as much as it is an *obfuscation*. That the numbers change is not important, as only the pattern in them will lead to the answer, which is of course constant.

**Note #2:** There was a bug in my post for a short while, which made the hint and puzzle basically the resolve to the same answer. This is fixed now. If you saved a copy the numbers before, just grab a fresh set.

## Solved!

The second landmark was discovered by Batuhan Bozkurt, congratulations! The challenge has not yet been met entirely, though so I've decided to set a new challenge with the same method. ~~The same $100 prize applies~~.

Redditor Bearasaurus has solved the final challenge too! For hints, check the followup post.

## Comments

Big Ben

I'm afraid Big Ben is not it. But be sure to include some explanation as to how the answer was reached, so I know it isn't just a random guess.

I "solved" your puzzle, but I assume not in the way you wanted.

After giving it quite some hours, I failed to find any specific pattern (with a reasonable kolmogorov complexity) that would lead me to an answer. But in Reddit, you mentioned that you would be interested in statistical approaches that would lead to an answer (which I assume you are interested for increasing the security of the obfuscation?) so I exploited the fact that your website gives fresh batch of numbers at each reload so I grabbed about 1000 sets (with intervals in between, hopefully not causing trouble to your website, it handled the requests like a champ) and got to cracking.

Now your HTML formatting implies 10x10 blocks of data for each set. So that was a starting point when I first began looking at the problem. The grid is 70 x 20 so that implies 14 secret codes, 7 for each row.

I looked for what was common for each 10x10 block in each of the samples I gathered from your site. I found out that for each 10x10 block some digits occasionally never appears; for example in block 0x 0y, not all digits have to appear but one always appears at least once.

Once I looked at the remaining digits (that are common in all blocks at a particular coordinate), for the "hint", I was faced by these digits:

0485130

0021739

These are the coordinates in the form of degrees-minutes-seconds (dddmmss as you gave away generously in Reddit) of Eiffel Tower.

Once I ran the same process for the puzzle, the result was:

0295845

0310804

Which is the coordinates for the Great Pyramid of Giza.

Maybe this is disappointing, I don't know. If the website hadn't provided fresh batch of numbers, this method would not work. I assume, to strengthen the obfuscation, you could make sure one digit always appears at least once; but as long as the distribution isn't random, I suppose the answer could be extracted.

I've tried many approaches before this; I'm pretty confident that the pattern is not based on neighborhood relationships (as the answer can appear on edges, though wrapping around could be employed but still with it I failed to detect any patterns). I think it doesn't have anything (or much) to do with arithmetic on the digits (like summing / subtracting them). I tried various row/column patterns and couldn't come up with anything.

I also analyzed the 10x10 blocks containing the answer digits only once (so if the answer is 0 for that block, 0 appears only once in that block). But saw no obvious pattern at all. So this beats me in that regard.

If I am eligible for the prize for my answer, I would kindly ask you to donate it to the Doctors Without Borders foundation. If you are uncomfortable about it for some reason, you can choose to donate it somewhere else you see fit.

Thanks for the challenge, and although my curiosity has been partly satisfied, I'm still waiting for the answer that will allow me to solve this using a pen and paper using a single set of numbers.

Batuhan, the answer is indeed correct. The Great Pyramid of Giza is the one I was looking for. The method you used is indeed not the one I was hoping for, as you haven't actually figured out the way the coordinates are encoded into the sets of numbers.

Still, I'm not one to dictate how the problem should be solved. I will make a donation to Doctors Without Borders for $100 in your name and post proof that I have done so.

Since I would very much like for somebody to solve the method, I'm including this static problem for a second attempt, and another $100. Being in a comment, the following set obviously does not change and encodes a third landmark.

2626513077384364666346599932245309032974209496921885110948315551555613

6549028370497764766953274173448611231555969009312435020244378244262894

9308377132331493394457637801172312372974892873367485438142538547446457

5987478672136633636156339295109196283474021313920015080695500005010510

9318473400638833698356337893287640679475088481921818727043921551931599

5758758671181690400516397336912974972974211231362065019596695870416497

1701226107698865022553554534544375771374969996927993180831110067651597

3203310324331357320447629709425333533533932743923435767555759732852649

0008077080336367751344339394399228589625005440340517458583553308156594

7467243472134765226056779555595344734475199118911888022882025906466417

0332300493776667648725560571112261196221231229957486429403779342535143

1366338577707417047142278890548676887286598087756091175002210326130060

5863902088494574497542911473583959753975898054668946115111760583633056

3673921092972792959782223331128568968982838265801286279605628360969080

5301986352763553665223261861393193111359891776463941295493449120391390

0463999640662807648743557375531417213379281451584481179187119326988940

4352555243298062697573961379660934698929891289118894828988929160129317

1871110111741174649945428445570098658283038728302510575750510526949009

3326333663020967498782260828822839081251556075505536114445618120357157

5602990599311067698721073220721651596922796029092045295295550390501233

The challenge now is to find the answer and a step by step description of how to extract the correct digits from it.

## Post a comment