## On the Subject of the Gridlock CM

A machine that knows no bounds when it comes to ciphers.

Create a key using the keyword on screen 1 and the Boolean Expression on screen A. Make sure to replace any Js with Is. Rearrange the key into a 5×5 matrix. This will be referred to as the Gridlock Key.

Take the digit string from screen 2 and place a cursor at the 1st digit.

For each letter of the encrypted word, do the following:

• 1: Start at the space that contains the Nth letter of the encrypted word in the Gridlock Key.
• 2: Repeat steps 3 - 6 until you reach a gridlock.
• 3: Mark the space that you’re currently at.
• 4: Add the digits in the digit string at the cursor and to the right of the cursor, modulo 10. Append this digit to the digit string.
• 5: Take the digit at the cursor and turn it into an instruction via the Instruction Table. Move the cursor to the right 1 digit.
• 6: If the instruction tells you that you’re in a gridlock, the current letter that you’re on becomes your Nth decrypted letter.
• 7: Reset the Gridlock Key so that all the spaces become unmarked.

Finally, if any of the letters on screen 3 match at the same position as any of the letters of your decrypted word, replace that letter with a J. You should now have a decrypted word.

### Instruction Table

01234
Move N, wrapping around, until you reach an unmarked space. If you can’t, then it’s a gridlock.Move NE, wrapping around, until you reach an unmarked space. If you can’t, then it’s a gridlock.Move E, wrapping around, until you reach an unmarked space. If you can’t, then it’s a gridlock.Move SE, wrapping around, until you reach an unmarked space. If you can’t, then it’s a gridlock.Move S, wrapping around, until you reach an unmarked space. If you can’t, then it’s a gridlock.
56789
Move SW, wrapping around, until you reach an unmarked space. If you can’t, then it’s a gridlock.Move W, wrapping around, until you reach an unmarked space. If you can’t, then it’s a gridlock.Move NW, wrapping around, until you reach an unmarked space. If you can’t, then it’s a gridlock.If all the spaces orthogonally adjacent, wrapping around, are marked, then it’s a gridlock. Otherwise, mark all of those spaces.If all the spaces diagonally adjacent, wrapping around, are marked, then it’s a gridlock. Otherwise, mark all of those spaces.

#### Example

Encrypted Word: KXZLVH
Screen 2: 326
Screen 3: ENVRLX

 A B11 C10 D* E7 F6 G H I* K1 L2 M3 P Q* R4 U V* W* X5 Y* Z* T9 O12 N* S8
 K L M R X X F E E S T C B O O 3 2 6 5 8 1 3 9 4 2 3 6 5 9 1 4 0 5
 A B6 C D E F* G H* I K L M P Q3 R U V W4 X1 Y Z* T O5 N2 S
 X N Q W O B B 4 0 5 4 5 9 9 4 8 3
 A2 B* C D5 E* F* G3 H4 I K L* M6 P* Q R U* V8 W7 X Y Z1 T* O* N S
 Z A A G H D M W V V V 4 8 3 2 1 5 3 6 8 9 4 7 3 1
 A* B10 C* D E15 F* G12 H5 I K2 L1 M13 P4 Q7 R U V3 W6 X8 Y Z* T11 O9 N14 S
 L K V P H W Q X O B B T G G M N E 7 3 1 0 4 1 4 5 5 9 0 4 9 4 3 3 7 6 0 3
 A B C6 D E F G* H I* K L3 M P Q R U2 V1 W X Y Z T5 O4 N* S
 V U L O T C C 6 0 3 6 3 9 9 2 8 1
 A* B7 C* D* E3 F* G6 H1 I2 K* L M5 P Q* R U* V W* X* Y Z* T8 O* N S4
 H I I E S S M M G B B T T 2 8 1 0 9 1 9 0 0 9 0 9 9 9 8 8

OBVECT + ENVRLX → OBJECT

Decrypted Word: OBJECT