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

0	1	2	3	4
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.
5	6	7	8	9
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