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

Posted at 2012-11-17 02:35:21 by SHD

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:

2704036679
6957154529
0077109676
8784804616
5482096079
9969999626
7555951579
6248226687
9901904019
2888988029
9357099530
0934884888
9980399999
8557055358
0384334383
8337383404
9984046902
0987808800
9587095189
3357329498
0977798777
7979898878
2112187211
2427440742
1779912799
2481098819
0955612811
4893618747
6941790771
8064408717
0048998004
4745337254
3069636000
9925459454
0972999992
0925342275
9968474204
9045774571
0028607132
3925488658
0623989781
0434438839
7533519137
9534144564
0613940281
0139111191
0654454440
7417971277
5531955519
9623692262
4173036146
1713442078
3032816067
4989616766
1080630777
0081118066
4776435047
2625572566
5171710157
6877786778
0530534095
7094975749
6063326300
3101203312
4136335146
6049636712
2054105326
5417905746
2896036149
8327835709
7397793497
6266464432
8304843088
4406458464
9877970987
1544473497
9188390984
8606050969
5090794498
5077653432
8180882819
4147906480
4962809830
5980986260
4127983540
4982999989
5980090550
8189888981
8827272278
3162003668
4304004334
7773737277
5567476645
9299469430
2522150126
1385857134
7679176136
0233079424
2232160372
5096867420
3736003091
5516824430
5463218362
3767012758
0466924639
0596790772
2667007776
3413222434
5743935344
3966896839
6565701956
8792474909
0706650951
3396258806
4140499991
8474774881
0090009309
1959151991
9692998921
5979575956
5787447777
7977077799
3108031050
3938433483
9752759277
3958727746
6987746630
7788457412
9937013383
9757425197
3278777888
0754757404
6826464862
2057757727
2384778892
2054725309
2774758616
2274754899
3958459798
2278788997

The puzzle

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

6821566851
9997947909
2290990929
4411114141
3404550134
1213450929
7769914941
5405640130
5816064159
8399814121
4457444444
5631066550
5429094759
2063161061
3428773332
5467787877
3459490443
3028643264
5633118713
5468450570
6435154651
2966662666
6239629602
5451010005
9248994242
6238162813
9456981214
6445631042
2459230496
2438692693
8545685744
3975991719
3125968746
8425625669
3175943538
3039993330
0345950453
0127620621
7575257725
8919495488
0168780685
0996095048
0186701136
0018727824
0185508234
6968393688
0036560403
0189701788
9141719741
8195018190
9052590555
5674776757
8731387887
7827676628
5754119145
8724501792
9657627933
7734789201
8657924697
7624776417
3850219013
7655839368
9114419347
8109741048
8958499066
8181311368
4461651046
6373747063
1218119217
9485899548
0775675757
3250205528
5336636633
9195595995
7149719797
7390548984
3140714197
0476533170
0275252270
9136542092
5435352433
3923923928
7280070398
1222123121
5532532568
1863833931
5394650323
1615073198
6342225128
0797270323
8305666580
0877200778
9033030339
7473573344
2260775277
7030723824
7877049237
8205213990
2465570607
0663611792
3997273792
2363366503
8777798727
4054430458
3743779347
1374279442
4929670348
2467530708
0792675503
7666199747
7765454065
6691449944
8360663630
6694339966
5900759795
6694782191
6660492947
5991492201
7765477953
8796482889
2097227229
4888999982
3590990999
2277447424
5807558858
3897909185
5027973710
4278465118
2297901010
2207927022
0244292701
0857491420
2158373250
4000783050
9881673400
0922772209
1581181358
2484323421
9990091090
2390093200

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.

Tags:

Comments

Big Ben

Posted at 2012-11-19 09:55:28 by Colin Edward

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.

Posted at 2012-11-19 13:48:31 by Steven Don

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.

Posted at 2012-11-19 16:36:10 by Batuhan Bozkurt

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.

Posted at 2012-11-19 17:10:02 by Steven Don

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