cipher - Lost in Translation: The Test

This just in: an alien message was received on Earth!! It seems some extraterrestrial species has contacted us in a language with symbols similar to our own--presumably for our convenience. You, a rookie code-breaker, want a shot at deciphering their message, but NASA is not allowing just anyone to see the message so they're holding a test of abilities for any code-breakers interested. Those who can prove their mettle will be allowed access to the classified info. You show up for the test and are given a sheet of paper that reads:

Welcome code-breaker! Here's your chance to prove your abilities: this will be a test of your abilities to translate unknown languages. Consider it a warm-up.

Below is a short 'Rosetta Stone' for a language developed by a mystical religious cult long ago (no records exist of this language, so don't attempt to search for it). Can you use it to determine how to transcribe from English to their writing system? Fill in the sheet with the translation rule(s) and tell us what this group worshipped, in our language and theirs. Good Luck!

English phrase:
THE QUICK BROWN FOX JUMPS ABOVE ANY HAZEL BRAVE DOG

Above phrase written in mystery writing system:
C2A 3M7I8 F3P71 O47 3M287 J0GLD 62B 4N2I8 E95LH 31K

A few quick notes we almost forgot: This language is similar to our own in some ways (it can express all of our letters for example) but dissimilar in one important way. Look for patterns and you'll figure it all out.

Answer

The solution to the cryptogram is the following:

We have a substitution code that is reversed. The code directly translates to: GOD EVARB LEZAH...KCIUQ EHT

Explanation:

Notice how we have letters A-P appearing and the numbers 0-9 appearing.

The sum of these letters and digits is 26.

Next, we note that '3' appears quite frequently - but strangely, it doesn't correspond to any values directly prima facie. If we take note that the only words that end in '3' appear three times, as do those words that end in 'E', we quickly find that the above solution is the case.

THE QUICK BROWN FOX JUMPS ABOVE ANY HAZEL BRAVE DOG
K13 HL59E 8I2N4 B26 DLG0J 782M3 740 17P3F 8I7M3 A2C

Key:

ABCDEFGHIJKLMNOP0123456789
DFGJKLMQRSTUVWYZPHOENIXABC

So they worship...

Phoenix

geometry - Find smallest rectangle divided into figures so each figure has 5 neighbours

The following 3x4 rectangle can be cut into pieces along grid lines, so that each piece has exactly three neighbors:

Problem: Find the smallest rectangle on the integer grid that can be cut into pieces along grid lines, so that each piece has exactly five neighbors.

Pieces are neighbors, if their boundaries touch; touching in a corner doesn't count.

Answer

How's this?

I got this by square-izing the icosahedron graph:

geometry - How many different non congruent polygons can you make on a 3x3 dot grid?

There is a $3\times3$ dot grid. How many different non-congruent polygons can you make on the grid?

Rules:

1. All vertices of the polygon must be on the grid


2. Only non self intersecting polygons


3. Only polygons with non-empty interior (<=> positive area)

visual - Solution Is Clearly An Image

As the title suggests, the answer is an image.

More specifically, you have to find the 7 character long imgur ID for the image:

imgur.com/□□□□□□□

Each character can be any letter A-Z (case-sensitive) or a number 0-9.

These are 7 little puzzles you have to solve, each corresponding to one character in the image URL:

1st character:

2nd character:

3rd character:

4th character:

5th character:

6th character:

7th character:

Good luck!

P.S. I'm not that familiar with the tags, so feel free to suggest edits :)

Answer

The image is ...

... the one with id J3gt6dw:

(The image was first found by Silenius. My first guess had the t wrong.)

1st character:

J — Converting to digits with A1Z26 gives a sum of 10. Converting back yields J.

2nd character:

3 — Highlight the cells in a grid that has rows and columns labelled from J to N. The first letter is the column, the second is the row. The highighted cells show the digit 3.

3rd character:

g — The layout shows a column on the keyboard. A1Z26 means that the top letter is T, the bottom letter is B. The letter is a G.

4th character:

t — The missing piece of the grid that i covered by the arrow tile looks like a capital T. This was found by young_nectar and also confirmed by the OP.

5th character:

6 — Conerting with a1Z26 gives SIX, or the digit 6.

6th character:

D — This looks like arithmetic with roman numbers: −1 + 10 − 5 = 4. The roman number for 4 is IV, which isn't a single letter. We need a small letter here, so I'm guessing A1Z26 again, which would be D.

7th character:

w — The missing digits are 23. Converting to a letter via A1Z26 gives W.

visual - A Letter: When Sherlock meets Moriarty

After the flight, I returned to my flat, 221b, Baker Street. I knew that Moriarty was at my place. There were some muddy footprints outside my room. But not just a single person, 2 or 3 people.

I opened the door and said "Hello Moriarty!".

The reply came from Moriarty who was sitting on the chair, "It has been so long Sherlock. A year maybe."

"Any reason for this sudden meet?" I asked.

"Yes. We need to end this."

"I thought you were having fun."

"Yes. I was having fun. I have something else to do now."

"What's that?"

"We'll talk about it at my place. I'll meet you there."

Then as Moriarty left the place from that opened door, I saw a stain of blood on his shirt sleeve. Who did it belong to? Was he on a killing spree, again? I closed the door after he left. While thinking about it, I saw two notes on the table.

The first said:

I won't be in the city for few days. Please take care of yourself.

-Mrs. Hudson

And the second (which looked more like a letter) was:

The door of your flat is locked. You can open it though, by entering a word in the machine near it. But you need to solve something for that word. I have sent you a picture. Look at it. Solve it using the five basic elements of life. Earth, Water, Fire, Air, Space. Find Answer To Enter the Door.

What? These elements don't really fit in that. Use the languages, Sherlock.

-Moriarty

Now I knew about those footprints of multiple people. They belonged to the people who fit that thing on my door.

I got his message after a few seconds.

Huh? There are no numbers. Only the clues in his note. And where are the "languages"? What is the word that I am supposed to feed in to the machine to get out of the flat?

---

Update

Moriarty has sent me a message. He's probably tired of waiting. The message is:

Can't you see that image clearly?

Answer

Here is the crossword filled in:

Original Image with a color change yields this:

Then with words added you get this (unfiltered):

How I arrived at those languages:

If you zoom into the image (or change the colors) you can see the languages Welsh, Esperantu, Albanian, Spanish, and Frisian. Translating Earth, Wind, Fire, Air, Space into the language that corresponds to the Language with the same first letter yields the crossword
Espacio -> Spanish for space
Tero -> Esperantu for Earth
Dwr -> Welsh for water
Ajror -> Albanian for Air
Fjoer -> Frisian for Fire

Possible Answers:

Fated -> first letter of each word anagrammed (pointed out by @f'')
Oreo -> The four intersections of the words spell out Orea (pointed out by @Chris Cudmore)

EDIT:

Moriarty wrote in the letter that "Find Answer To Enter the Door". The capital letters are FATED. So it is the word.

combinatorics - Rotationpuzzle in hex - The journey beyond the tomb

This is the 3rd themed puzzle of the tomb. (See puzzle 1 and puzzle 2) It is fully independent of the other two and just linked by the common story.

---

After you set the colour-puzzle dials to the right combination, the whole apparatus gives way to a tunnel underneath. A dark-grey metal-ladder leads downwards into another cavern, and it takes you just one a glance to see, that your ordeal in puzzle solving is not over yet. Built into a green marble wall is another device full of colourful crystals, and odd little turning wheels in two shapes.

Without much thinking, you start turning a few of them over, and you can feel that they snap in distinctive steps of 120, respectively 60 degrees. They can also only be turned clockwise. Other than that, nothing seems to happen.

After you turned a dozen or so steps on multiple wheels, there is 'clicking' sound and the wheels all start turning backwards. When they stop again, the panel glows greenly and becomes transparent, and you can see that underneath the panel are crystal markings in the same five colours the crystals on the surface have.

The transparency fades away, and you repeat your experiment. Again, after 25 'steps' on the wheels, there is the clicking, the sequence of the turns is reversed, and the panel becomes transparent for a few seconds again. You play this game a few times, until you've firmly established that you can turn an arbitrary amount of wheels for an arbitrary amount each, until you reach the total sum of 25 steps. Then the device seems to reset itself to the starting position by reversing the moves, and the starting position is shown through the transparent panel. You also establish that the starting positions is always the same.

Convinced that you have to fine the right combination to proceed, you look for further clues around you. Only when you turn you attention to the ceiling of the cavern do you discover the two painted pictures. With a deep sight you start un-puzzling this puzzle. It's too late to turn around anyway.

---

Is to find the right combination of the wheels to turn. The picture of the device below has the wheels labelled for ease of notation.

Each "turn" of a wheel is denoted by a single appearance of the label, i.e. turning FF2 means that wheel F is turned twice for one step and afterwards wheel 2 is turned for one step (all clockwise).

The pictures on the ceiling are:

And the transparent device looks like:

---

The solution of this puzzle is the shortest sequence leading from the start situation to the final situation.

I do know a solution of <25 steps exits, but it might be possible to achieve this with less moves than my solution. If so, the sequence with least steps will be accepted as final solution.

---

As always, I'm highly interested in thoughts and comments on both the puzzle and its solution.

Answer

I did it in these 17 moves:

99C423EDDBBB6CC88

Here is the initial position I used:

Here is the position after I solved it with the 17 moves above. The textbox in the top left corner keeps track of moves made, but I crossed through it with a black line so that it wouldn't give away the answer to those who didn't want to see it.

How I Solved It:

It was very hard to figure out using only the pictures, so I did 2 things:

1. Converted the color paths part of the puzzle to numbers, and oriented them correctly on a piece of paper. (not shown here)
   


2. Created a quick and crude graphical way (using C# WinForms) to rotate them, based on the 15 different levers.

Since I could not (easily) rotate the hexagons on the graphical part, I solved it first without rotating any of them, but then had to use paper cut-outs to check that each hexagon was oriented correctly also. And they were.

The set-up took almost all of the time(3-4 hours since I set it up wrong the first time and then solved THAT problem too before realizing it was set up wrong! haha). Solving it took about 15 minutes. And checking it took about 45 minutes, due to me having to cut out 35 hexagons and set up the initial position, and then carefully perform each of the 17 moves.

logical deduction - 1000 logicians wearing hats

Pre-game: There are 1000 logicians in a line, each wearing a black or a red hat, completely at random. No one knows the color of their own hat. Each can see the hats on the next 10 people. The logicians are allowed to communicate before the game, but not once the hats have been placed.

Game: Starting with the back, each logician must call out loudly, a color, red, black, or white. White is obviously always wrong. This calling is, however, the only communication in the game. Every person who fails to say his own hat color is silently killed.

What is the best strategy for the logicians?

Twist 1:

Suppose there is exactly one blind man in the line. His location is not known to anyone, but he can hear and speak.

Answer

The person in the back looks at the next $10$ people and adds $1$ for each black hat and $0$ for every red hat. If the sum is odd then he says "black". Otherwise he says "red". This gives him a 50% chance of survival.

The next 10 people can sum the 9 people they can see or have heard the color of from their block of 10 people. If their sum is the same parity (even or odd) as the one the back person had, they yell "red". Otherwise they yell "black".

The result of the limitation that each peson can only see 10 people ahead of them is that no information from the back person will continue to person 12. This means he will behave as a new back person. This means that the people in positions $1,12,23,etc$ labeled from the back are forced to act as "back" people and therefore have a 50% chance of survival. On average 45.5 people will die each game.

Twist 1:

The effect of a blind person will depend on his position $\mod 11$. If he is in positions $1,12,23, etc$, ($1 \mod 11$) guessing means there is a 50% chance he will die and there is an independent 50% chance everyone in the next 10 will die. He should say "white" which will kill him, result in the person in front of him having a 50% survival rate and the next 10 people after the person in front of him a 100% survival chance. If this occurs, on average 46.5 will die.

If he is in position 1000, he should just guess; everyone else has already gone.

If he is in position $11,22,etc$ ($0 \mod 11$) he has a 100% chance of survival because he could hear what everyone said.

If he is in position $10,21,32,43,54,65,76,87,etc$, ($10 \mod 11$) when he guesses if he is correct, both him and the person in front of him survive. If he is wrong they both die. If he says white, he dies and the person in front of him acts as a back person. If he guesses, on average 46.5 people will die. If he does not guess, 47 people will die on average. This means he should guess.

If he is in position $9,20.31,42,53,64,75,86,etc$, ($9 \mod 11$) when he guesses if he is correct, both him and the 2 people in front of him survive. If he is wrong they all die. If he says white, he dies and the person in front of him acts as a back person. If he guesses, on average 47 people will die. If he does not guess, 47 people will die on average. It doesn't matter if he guesses.

If he is in any other position, he should say "white". This means the person in front of him will act as a back person and, on average, 47 people die.

This means if the blind man is moral and randomly placed on average 46.8 people will die.

chess - How to control the whole board with 8 standard pieces?

How to control the whole board with 8 standard pieces (one king, one queen, two rooks, two knights, two bishops)?

P.S. A piece doesn't control a cell simply by staying on it, so another piece must control it.

Answer

It's a studied problem: Oxford journal page

The three possible solutions are listed at the top of page 4.

Also noteworthy: there has been no option found with the bishops on opposing colors.

logical deduction - A well balanced puzzle: Logic puzzle(s) in visual disguise

This is a rather involved puzzle and might require a bit of stamina. All of the puzzle is in image form. The introduction text is not needed for the puzzle. At the end of the puzzle you'll get a short English sentence. The puzzle consists of several sub-puzzles and you're encouraged to post solutions to the individual steps - I will comment on them.

The puzzles has now been fully solved, and the complete solution is summarized in the accepted answer.

---

You're in a circular room with a dome-like ceiling. All walls and the floor are bright white. There is only a single, metal door, which has a small, circular whole in eye height. You don't have any recollection how you came here, but at the moment, you're really only interested in getting out. The door, is looked. You knock, and there is some movement behind the hole. Somebody comes to the door and talks through the hole. The voice, however, sound foreign and not very human: "You awake? You out? You say passphrase!"
You are about to ask something, when suddenly the walls behind you begin to shimmer and form a series of images, and the voice through the door adds: "You clever? You find passphrase."
Whatever else you say to your capturer, the only answer you get is: "No, not passphrase."
It seems you really have to find the passphrase. You just hope you can, before you die of hunger and thirst.

On the wall around you, the following images can be found (The appear clockwise around the room starting with the door and ending with the door.)

---

---

(Instruction 1)

(Instruction 2)

(Instruction 3)

---

(The bottles)

---

(The scale)

---

(The code)

---

(The keys)

---

---

The following image is auxiliary for convenience sake. It is a close-up of the bottle labels of the 2nd image above.

(Bottle Label close-up)

---

---

---

---

As always, I'm interested in your ideas and feedback. In particular, I hope the puzzle is fun. If it isn't, let me know why. If it turns out that the puzzles needs amendments or changes to become better, I'll edit them.

---

The red ABCDEF/1234 labels are not required for the puzzle. They have only been added to make it easier to discuss/describe solutions.

The 6 'rod-shaped' objects in the last image fit in size into the 'slot' of the image with the letters above it. (As shown in the smaller black & white image.)

You may use any tool etc. to solve this puzzle, but it should be perfectly possible to do this with pen & paper alone.

---

HINTS

If you are really stuck with this puzzle and are wondering along the lines of "What the @£! am I supposed to solve here??" you may look at the following hints. But they will spoil a bit of your fun (as all hints do.) I try to make successive hints revealing more and more, so just try one at the time...

Where am I even supposed to start this??

The first images until the first horizontal line are called instructions for a reason. Try interpreting them in terms of what is this puzzle about? and what am I to do?

I still don't get it at all...

Remember: At the very end of the puzzle is a pass-phrase. The only image with letters is obviously important, but how could one encode with it - using the previous images? It surely can't be done with one image alone...

But... There are endless possibilities! I could read anything out of this...

Really? Is there no clue about the length of the pass-phrase? Does this length match anything... ?

Okay, okay, so what do I have to solve first ?

The puzzle has 3 main-sub puzzles. Guess what, they are sorted that way. Let's call them the bottles, the scale and the code puzzle. The scale is (literally!) the central puzzle here. It provides the information needed to solve the code. But in order to attempt the scale you need information provided in the bottles. What could that be? Have another look at the instructions! What do the yellow squares symbolize? What does the blue-to-grey shading symbolize? So what could the labels then be for?

All nice and well, but can you give me another hint?

NO. If you are still stuck and don't want to spent more time on thinking, you might as well read the accepted solution below!

Answer

This is a community-wiki answer compiling the final solution of the puzzle.
It also presents the solution as intended.
The solutions were found by individual answer posters.

For the impatient, the final answer is:

"Balance is the rectifier"

Individual contributions were:

Gary Ye:
- First discovery of mechanism of part 1 (The Bottles)

i_turo:
- The full solution to part 1 (The Bottles)

EFrog:
- Final sorting detail of part 1 (The Bottles)
- Valuable ideas on how part 1 and part 2 are related.

Bulldogg6404:
- The mechanism of part 2 (The Scales)

Nephtyz:

- The first solution to part 2 (The Scales)

Bulldogg6404:
- Missing colours on the scales. (The Code)
- The mechanism and solution of part 3 (The Code)

---

---

Instructions

• 
  
  

  All images: The blue-to-grey gradient everywhere represents:

  
  

  
  

  order. Otherwise identical bottles (they are all blue) have to be sorted in some way and then be used in this order.
  Also: The final pass-phrase is gotten letter by letter in correct order.

  
  

  
  


• 
  

  Instruction 1 (left part)

  
  

  
  

  The original grid of bottles is not in order. The labels and the yellow code-grid-table need to be used to achieve sorting. For the meaning of the code-grid-table see 'The Bottles'.

  
  
  

  
  


• 
  

  Instruction 1 (right part)

  
  

  
  

  Bottles are labelled by dots, indicating the amount of liquid they contain. Filling a bottle into a tube will fill the equal amount of square grids, starting from the further most grid. Other details to be seen: The liquid does not level out across neighbouring squares. The spacing or alignment of 'dots' on the labels is of no consequence. (The shown bottle has 5 dots in an arrangement none of the bottle labels has.)

  
  

  
  


• 
  

  Instruction 2

  
  
  

  
  

  The 24 bottles are needed in 'The scales'. They are used in the order determined by 'The Bottles'. They need to be filled into a single tube one after the other, while the hanging weight is moved at each step to keep the scales in balance.

  
  

  
  


• 
  

  Instruction 3

  
  

  
  

  One key is the final puzzle piece. It is needed to complete the second part (The Scales). This single key needs to be inserted into the code-table. The pass-phrase is found letter-by-letter from the grid. There are as many letters as there are bottles (24), and their order is the same as determined by the first part (The Bottles).

  
  

  
  

The Bottles (solved)

The aim of the bottle puzzle is to bring the 24 labelled bottles into correct order.
The brown bottle labels are a transparent grid. If all are overlaid, only a single square remains fully transparent.
It is only possible to remove a specific label from the stack in order to get a second transparent square. (Removing any other label doesn't change the situation.)
Once that label is removed, there is only a single specific label which can be removed in order to get a third transparent square. etc. etc.
This gives an order of labels. However, it is ambiguous as it is not clear if the order is first-to-last, or last-to-first.
Checking the position of the "first" and the "last" transparent grid-square on the yellow code-table of hint reveals: Alpha and Omega.
Alpha and Omega are the first and last characters of the ancient Greek alphabet. They are often used (f.e. in religion) to indicate Beginning and End.

Therefore the correct order of bottles is with the first label removed showing 2 fields and the next showing 3 fields etc. As all bottles are equal except the grid and dot labels, and the grid has been 'used up' by the puzzle now. The 'dots' are all that remain. 'Dot-labels' sorted by the order determined above are:

Spaces in the dot-labels are decoys and can be ignored.
The number of dots in sequence (ignoring any spaces) are:
5; 3; 7; 2; 4; 3; 4; 4; 5; 2; 3; 1; 6; 2; 3; 4; 6; 5; 6; 2; 1; 4; 4; 7

---

The Scales (solved)

The balance of the scale is determined by

the total weight of filled pipes and the hanging weights.

Each 'filled square' counts for the same weight, and the tipping moment is determined by the (horizontal) distance from the centre point multiplied by the (summed) weight at this distance.
An example (tipping to the right by "+2"):

Following Instructions 1, it is the aim of the puzzle to ...

...fill in the bottles one after the other into either of the 6 tubes, while keeping the system in balance with the hanging weight. The exact sequence has to be found by the puzzle! However, the order of the bottles is given (by the The Bottles puzzle) and there is only a very limited number of possibilities which can keep the system in balance at each step.

Following all of the above, the puzzle solves into the following sequence:

Read the image left to right and top to bottom for the sequence of 24 bottles subsequently filling the pipes:

A second solution is possible, which has bottles 11 and 15 swapped. However, only one of the two solutions (the one above) will produced an English pass-phrase in the third part of the puzzle (The Code).

---

The Code (solved)

The solution of part 1 and part 2 of the puzzle give one

24 ordered actions of pouring bottles into the grid. Each pouring-actions is defined by 2 things: A tube colour into which the liquid is filled and a hanging position for the balancing weight. This position is associated with a colour, but some positions are missing.

The missing (b&w checkboard pattern) fields on the scale can be found by

looking at colours of all keys. All 6 keys show the same colour 'pairs' albeit in different vertical ordering. The according colour pairs appear in symmetric position on the scale as well, allowing to fill in the spots as with the following image:

Also: Colour-pairs (if watches as RGB hex-codes) add up to FFFFFF, i.e. are complementary.

Labelling the 26 weight-hanging positions from the left to the right, one gets the solution as a table:

To find the appropriate key for The Code one has to...

...realized that the final situation after pouring all bottles left exactly two red squares empty. On the bottle, the squares are represented by yellow diamonds. The same dots appear on the keys, so the two yellow diamonds on the red key will 'complete' the puzzle as hinted at by 'Instruction 3'.

With this key inserted into the code-table...

...one can now translate the 24 pairs of 'pipe colour' and 'weight position' into letters by looking them up in the grid:

This eventually leads to the 24-characters of the pass-phrase:

BALANCE/IS/THE/RECTIFIER

story - The SErial Killer (Part 2)

This puzzle is part of a series - part 1 is here. Any comments I make on the OP are canonical and out of character (OOC). Any comments I post on answers are for flavour only.

Update: As it turns out, this was a very easy puzzle, and I'm actually having to rewrite the plot of the series thanks to SKV being far too clever for his own bleeding good (I love you really). The glory's gone, but try to solve it without checking out the answers. I enjoyed making it, anyway :-) Part 3 will be tougher.

---

You're staring at the list of Stacks when out of nowhere, you hear a voice going rik tika tik tik tik tik and before you wonder where it came from you realise something - the capital letters in the titles of all the dead sites can be re-arranged to spell "Moderators"!

You cast your eyes over the the list of murdered sites to find the Moderators Stack, and in your best Scottish-detective voice you announce "Och! There's bin a murrrrrrder, and ah nae where ahm going tae look!" (OOC: Sorry, Scotland). Tentatively, you click through to the Moderators stack and right at the top, you see a post entitled "We Will Conquer". You recognise the title from one of the dead Stacks, so you click on to read it...

You gasp in disbelief and check back to the Stacks list - sure enough, Ask Ubuntu is dead. You're about to click on it to make sure, but then remember the ominous warning about entering a new Stack, and think better of it. This "Handel" character doesn't seem like someone to mess around with.

You realise you're suddenly on a countdown, trying to minimise the number of stacks that die, and every false step you make could bring a flood of confused newbies asking inane questions about anything on to your beloved Puzzling.SE... or even worse, Puzzling.SE might get killed off!

Baffled and starting to panic a little, you sit back to mull things over. What's your next move? Where should you look?

Answer

English language & usage. The ampersand in the logo has hex color 90383b, which is the roman numeral in the tag.

story - Lights in the Dungeon: Four by Four

This is the second in a series Lights in the Dungeon puzzles.

_{previous (1st) <-- | --> next (3rd)}

---

As you exit the three by three dungeon, you are greeted by a grinning Lord Hooty McOwlface. A grin does not make him appear friendly. Rather, you get the feeling that he's deciding which portions of you would be tastiest.

"Well!" screeches his Lordship, "Has he succeeded?"

It takes you a moment but you realize that he is not talking to you and is, in fact, addressing the purple cat sitting at a bank of computer terminals. You know this to be Fakky Jim, the Lord's grand vizier who is, by coincidence, a magic cat. He turns his furred head and utters a single, "Mreow."

"Drat!" says McOwlface. "I suppose we're on to round two, eh? Very good. The dungeon shall be larger but the rules are largely the same. Larger? Largely? I am hilarious..." He pauses for you to appreciate this but you can give nothing but a blank stare. He dismisses you with a wave. "See Fakky for the updates."

You walk over to the cat and retrieve a scroll. Unfurling it, you find the rules below (revisions from the previous challenge are in bold):

1. You will enter a dungeon in which there are many rooms. Each room has a single light in the middle. You must turn off every light.


2. The lights are easily turned off by a short chain hanging from the fixture.


3. As soon as you exit a room, the floor will collapse to reveal the thousand-foot chasm below. You may not re-enter a room and, therefore, must turn off each light by passing through each room exactly once.


4. The map below shows the current design of the dungeon with each room bordered by red and labeled with a alphabetic character.


5. You may rearrange the rooms however you like before you enter but you cannot change the overall dimensions of the dungeon. In this case, that means the dungeon must be four rooms wide and four rooms tall.


6. You cannot rotate or flip rooms. You may only translate them.


7. You may only enter the dungeon once and exit once. As soon as you exit the dungeon, any remaining floors will collapse.



8. If there are any rooms not visited and, therefore, any lights left on, you lose. If all lights are turned off when you exit the dungeon, then you win.


9. If you create a dungeon map that you cannot enter or cannot exit, you shall lose.

How can you rearrange the dungeon rooms so that you can win the game?

_{There are probably multiple solutions. The first valid answer will be accepted.}

ABBC
DDEF

GGHH
MMOO

---

For reference, here are the 16 possible rooms. (Note that this is all possible rooms. For this puzzle, you must use exactly the rooms shown in the map above.)

Answer

How about:

BGBC

HFMM
OADH
OGED

This has the nice additional quality that, no matter which room you enter by, you can still complete the path.