# Retrieve a phrase by assembling the string puzzle

You’ve never seen such a verdant shade of green as the leafy tops of the trees that now form a focal point up ahead, peaking over the high and solid concrete walls which surround Eden. The colour makes you uneasy, so you focus on the grey of the wall instead. Intellectually, you’re well aware that the leaves look like leaves are supposed to, unpoisoned, but it feels like you’re halluncinating after watching a particularly pristine old movie disc.

Set into the middle of the wall is an enormous metal door, polished and gleaming in the sunlight. The door sits adjacent to the termination of the dirt path leading up to itself, a symbol of Eden’s rejection of the outside world.

Your stomach is queasy with nerves as you come closer and closer to the door. You’ve never heard of anyone who’s successfully gotten into Eden from the outside world, or come out of Eden. You’ve never even heard of someone who’s tried and failed. Your eyes dart around the imposing surface of the wall, searching for turrets.

Though your steps grow ever shorter as you approach, you soon find yourself within knocking distance of the great metal door. You wrap a rag around your hand so as not to touch its hot surface and wrap your knuckles against the door three times.

Before you’ve even completed your final knock, a voice booms down from on-high.

“ONLY THOSE MAY ENTER WHO POSSESS THE KNOWLEDGE OF GOOD AND EVIL.”

You chuckle inwardly at the irony. “I have this knowledge,” you shout back to the voice.

“LET THE ONE WHO HAS THE KNOWLEDGE REPEAT THE PASSPHRASE FROM WHICH THE KNOWLEDGE DERIVES.”

You consider for a moment. “apple”

“INCORRECT. THREE ATTEMPTS REMAINING.”

“Apple123”

“INCORRECT. TWO ATTEMPTS REMAINING.”

“Apple123!”

“INCORRECT. ONE ATTEMPT REMAINING.”

Okay, it’s probably not going to be that easy.

“AND ON THE FOURTH FAILED ATTEMPT, THE TREE OF LIFE WAS REMOVED FROM THE UNWISE ONE.”

Right, better not waste that one. You survey your surroundings, in search of anything that might help you figure out the password. There’s not very much around that could possibly help you, but just as you’re about to give up hope, you see a very conspicuous red-coloured rock lying on the ground just next to the enormous door. A grimy slip of white juts out from underneath the rock.

You lift the rock and discover a folded piece of paper. Unfolding it, you discover a set of cryptic lines, written in small, neat handwriting.

OIOOb
_IOI0
OI_If
IOOO6
_OOO8
I_II9
II__3
_IOO1
O__I2
OIOI9
OOOOa
_III8
IOI_f
OO_Of
OIIIe
_OIO0
OOIOb
_IO_1
_IIO4
IO_Oe
OIO_d
__IOc
IIOIe
O_OO4
IIIId
IOIO9
IOOI8
IO_Ic
IO_I0
IIIO8
OO_I5
OOII8


So do as the title suggests if you can. Even if you cannot solve it, still all kinds of ideas are welcome.

The language is English. The title may include some clue; it is the original phrase of the puzzle.

• I don't know whether it is important but I've noticed that in first 4 columns number of Is, Os and underscores are 12-12-8, 14-14-4, 12-12-8, 14-14-4 respectively. Seams hardly coincidence to me. Hope it could help someone. – kamenf Apr 15 '16 at 11:11
• crybaba, is this a puzzle you have made or one someone else has set for you or what? It starts out sounding like it's one you've made, but what you say at the end and your comments here give the opposite impression. If it's someone else's puzzle, is there anything else you can tell us about it? E.g., where it comes from, anything else in its context that might suggest ideas, etc.? – Gareth McCaughan Apr 20 '16 at 14:56
• I don't understand. Surely it must have come from somewhere. – Gareth McCaughan Apr 20 '16 at 14:59
• To add to what @GarethMcCaughan has said, if it's not your puzzle you should link/credit the actual source. Plus the convention is usually, if you don't know the solution yourself, you state as much in the post (so that people know you can't provide clarifications/hints and that in extreme cases, the puzzle may be unsolvable). – Alconja Apr 21 '16 at 3:07
• @crybaba: I'm not sure whether you mean me here ("those who cannot solve" would currently appear to be the entire population of the world), but I'm not complaining, I'm asking. If this isn't your own puzzle, then it cannot be true that "there is no other context", and it seems like that other context might be useful. (And, as Alconja says, if the puzzle is someone else's then not crediting them would be plagiarism.) I can't imagine why deleting it would be a good idea, but of course you have the right to do that if you want. – Gareth McCaughan Apr 22 '16 at 11:33

After a little Googling, I found the answer here.

Basically:

The O,I and _ strings are pieces of a jigsaw puzzle and are read left to right with the 5th character being what's written on the piece.
The edges are figured as such:
If it's an _ (underscore) it's a flat edge, if it's an I it's a pip and if it's an O it's a hole.

With that knowledge in hand you can begin reconstructing the string. In the end, the solution ends up being:

1148008cfeb9dae4d68898b93e05cff2

Which I'm pretty sure no one would've guessed.

Either way as I stated in the beginning of this answer, I didn't solve this myself, but found the answer online.

• That solution must mean something. I mean, who in the world would have guessed that the answer is a combination of letters and numbers making absolutely no sense?? – Sid Aug 15 '16 at 14:49
• @Sid No idea, this is just what I found after a bit of searching. – dcfyj Aug 15 '16 at 14:49
• I believe that this is just a password for a separate file that was part of the Hackfu challenge. Unfortunately I don't know enough about decryption to verify this. – Daphne B Aug 15 '16 at 23:24