# Solution to Infinite Corridor Simulator

#### by Jon Schneider, ...

Infinite Corridor Simulator is the fifth and final type of puzzle unlocked in the Infinite Corridor round. True to its name, each Infinite Corridor Simulator puzzle looks a lot like a summary of the Infinite Corridor Round itself — more specifically, each Infinite Corridor Simulator puzzle contains a list of 100,000 similarly named and numbered puzzles along with their answers. For example, Puzzle 5 (the first Infinite Corridor Simulator Puzzle — we will use it as a running example throughout this solution) begins as follows:

 Puzzle 1 Unchained DELIRIUM Puzzle 2 Make Your Own Word Search EPISTLE Puzzle 3 Library of Images COP Puzzle 4 Unchained OBLITERATION Puzzle 5 Infinite Corridor Simulator DUSKY Puzzle 6 Unchained ETHICS Puzzle 7 Library of Images E Puzzle 8 Unchained ANTEROOM Puzzle 9 Library of Images CUSP Puzzle 10 Unchained HYPOTHESES Puzzle 11 Unchained PROM Puzzle 12 Infinite Corridor Simulator UDDER Puzzle 13 Library of Images Z Puzzle 14 Unchained ZITHER Puzzle 15 Library of Images LEVEL Puzzle 16 Unchained ENCROACH Puzzle 17 Cafe Five SEED Puzzle 18 Make Your Own Word Search WEAN Puzzle 19 Infinite Corridor Simulator KETCH Puzzle 20 Unchained SUPERHIGHWAY ...

These answer/puzzle pairings differ between different instances of Infinite Corridor Simulator and do not match the puzzles and answers in the Infinite Corridor round (with one notable exception). However, all Infinite Corridor Simulator puzzles use the same puzzle mechanics as each other.

If we take the first letters of each answer, we get the message DECODE EACH PUZZLE (after which the first letters devolve into nonsense). This suggests looking at all the answers of each type separately. When we do this, we find that we can solve each stream of answers as a subpuzzle to get an answer phrase of the form “[ordinal number] [digit]” (e.g. FIRST SEVEN). The solutions to each subpuzzle are detailed below.

The five ordinal numbers we obtain always include each of FIRST, SECOND, THIRD, FOURTH, and FIFTH exactly once. For example, in Puzzle 5, we obtain the five subpuzzle answers:

```FIRST ONE
SECOND SEVEN
THIRD ZERO
FOURTH THREE
FIFTH ONE
```

This allows us to form a five-digit number n by placing each digit at its corresponding location (17031 for the above example). Looking up Puzzle n in our list of puzzles, we find it is an Infinite Corridor Simulator puzzle — for example, in Puzzle 5, we observe:

 ... Puzzle 17030 Library of Images DUN Puzzle 17031 Infinite Corridor Simulator DRESS Puzzle 17032 Infinite Corridor Simulator EXILE ...

The answer to Puzzle n is the answer to this Infinite Corridor Simulator puzzle (and so for the specific example of Puzzle 5, the answer is DRESS).

## Subpuzzle solutions

### Unchained

The first few answers to Unchained puzzles in Puzzle 5 are:

 Puzzle 1 Unchained DELIRIUM Puzzle 4 Unchained OBLITERATION Puzzle 6 Unchained ETHICS Puzzle 8 Unchained ANTEROOM Puzzle 10 Unchained HYPOTHESES Puzzle 11 Unchained PROM Puzzle 14 Unchained ZITHER Puzzle 16 Unchained ENCROACH Puzzle 20 Unchained SUPERHIGHWAY Puzzle 26 Unchained FAROFF Puzzle 31 Unchained ASPIRATE Puzzle 37 Unchained OVERDO Puzzle 42 Unchained ASPIRANT ...

All of these answers have even length. In addition, the central bigrams of these answers often repeat (IR, ER, HI, ER, TH, RO, TH, ...). These central bigrams are randomly selected from the answer phrase — in particular, they alternate between being chosen from the first word of the answer phrase and being chosen from the second word of the answer phrase. From this, we can reconstruct the answer to this subpuzzle. For this specific puzzle (Puzzle 5), this leads to the subpuzzle answer THIRD ZERO.

### Cafe Five

The first few answers to Cafe Five puzzles in Puzzle 5 are:

 Puzzle 17 Cafe Five SEED Puzzle 22 Cafe Five SELFMADE Puzzle 27 Cafe Five LAM Puzzle 32 Cafe Five STREAMLINE Puzzle 36 Cafe Five RESENT Puzzle 40 Cafe Five TRANSFERENCE Puzzle 44 Cafe Five CRANE Puzzle 50 Cafe Five RECTANGLE Puzzle 57 Cafe Five LEG Puzzle 61 Cafe Five PENLIGHT Puzzle 67 Cafe Five PINT Puzzle 71 Cafe Five TREPIDATION Puzzle 76 Cafe Five TIRADE Puzzle 79 Cafe Five ANTIDEPRESSANT Puzzle 84 Cafe Five APTNESS Puzzle 89 Cafe Five PARENTHESES Puzzle 94 Cafe Five HER Puzzle 99 Cafe Five HALFBREED Puzzle 103 Cafe Five BLADE ...

Every other answer in this stream can be formed by anagramming its two surrounding answers along with an additional letter (for example, SELFMADE = SEED + LAM + F). Reading off these additional letters reveals the subpuzzle answer repeated endlessly. For this specific puzzle (Puzzle 5), this leads to the subpuzzle answer FIFTH ONE.

### Library of Images

The first few answers to Library of Images puzzles in Puzzle 5 are:

 Puzzle 3 Library of Images COP Puzzle 7 Library of Images E Puzzle 9 Library of Images CUSP Puzzle 13 Library of Images Z Puzzle 15 Library of Images LEVEL Puzzle 21 Library of Images MERRIMENT Puzzle 24 Library of Images AX Puzzle 29 Library of Images FRIDAY Puzzle 33 Library of Images JUMBO Puzzle 38 Library of Images AMP Puzzle 43 Library of Images CATCH Puzzle 48 Library of Images TRICOLOR Puzzle 54 Library of Images MORTGAGEE Puzzle 59 Library of Images HASHISH Puzzle 62 Library of Images CYNICALLY Puzzle 65 Library of Images WOE Puzzle 70 Library of Images AX Puzzle 74 Library of Images CUR Puzzle 80 Library of Images HOCKSHOP Puzzle 86 Library of Images THAW Puzzle 91 Library of Images SLOPPY Puzzle 96 Library of Images ON Puzzle 101 Library of Images AROUSE Puzzle 106 Library of Images HACK Puzzle 111 Library of Images IRE Puzzle 116 Library of Images NAB Puzzle 121 Library of Images ENVIABLE Puzzle 126 Library of Images SLY Puzzle 132 Library of Images SN Puzzle 137 Library of Images CONVICT Puzzle 142 Library of Images MILITANCY Puzzle 146 Library of Images LIKEN Puzzle 153 Library of Images F Puzzle 158 Library of Images BE ...

If we look at the lengths of these answers, we see that in order they are 3, 1, 4, 1, 5, 9, 2, 6, …, which we can recognize as the digits of pi. Indeed, the lengths of the answers match up with the digits of pi, with the exception that where the corresponding digit would be 0, the answer is a single character. The first such instance occurs at the 33rd digit of pi (counting the leading 3 as the first digit) — in the above example, this corresponds to the 33rd instance of Library of Images, which is Puzzle 153 with the answer F. Taking these characters in order reveals the answer to this subpuzzle. For this specific puzzle (Puzzle 5), this leads to the subpuzzle answer FOURTH THREE.

### Make Your Own Word Search

The first few answers to Make Your Own Word Search puzzles in Puzzle 5 are:

Many of these answers start with a compass direction (N, S, E, W) and some (e.g. SEANCE) even start with one of the four diagonal compass directions (NE, NW, SE, SW — however, NW will not appear in any puzzle). These answers are divided into chunks by answers that do not start with any compass direction (e.g. FLANK). The path we obtain by following the compass directions for a single chunk draws out a letter. For example, in the first chunk of six puzzles before FLANK, we have the directions E, W, S, E, W, S, which results in the following path: This path draws out the letter F. Drawing out these paths and reading the letters formed reveals the answer to this subpuzzle. For this specific puzzle (Puzzle 5), this leads to the subpuzzle answer FIRST ONE.

### Infinite Corridor Simulator

The first few answers to Infinite Corridor Simulator puzzles in Puzzle 5 are:

 Puzzle 5 Infinite Corridor Simulator DUSKY Puzzle 12 Infinite Corridor Simulator UDDER Puzzle 19 Infinite Corridor Simulator KETCH Puzzle 25 Infinite Corridor Simulator YOUNG Puzzle 30 Infinite Corridor Simulator UNWED Puzzle 35 Infinite Corridor Simulator DOWSE Puzzle 41 Infinite Corridor Simulator DIVER Puzzle 45 Infinite Corridor Simulator RAPID Puzzle 51 Infinite Corridor Simulator KNEAD Puzzle 56 Infinite Corridor Simulator ENSUE Puzzle 63 Infinite Corridor Simulator TONIC Puzzle 68 Infinite Corridor Simulator HUMOR Puzzle 73 Infinite Corridor Simulator YEARN Puzzle 77 Infinite Corridor Simulator UNWED Puzzle 82 Infinite Corridor Simulator GRIST Puzzle 88 Infinite Corridor Simulator UNDUE ...

If we read the first letters of these answers, we find that this almost matches the string we get by concatenating all the answers in order. For example, the string we get by reading the first letters of the above answers is

`DUKYUDDRKETHYUGU…`

and the string we get by simply concatenating the answers is

`DUSKYUDDERKETCHYOUNGU…`

It is possible to transform the second string into the first string by deleting some letters (approximately one per word, but occasionally more, and occasionally fewer). Reading the deleted letters, we find the subpuzzle answer. For this specific puzzle, the answer is SECOND SEVEN.