META-META
TasThiluna

## Solution

### Step 1:

The feeder answers are pieces of information that can be used to generate a key using the rules of Playfair Cipher.

1. According to Cheap Checkout, a SPECIAL DAY is Sunday. Start with BECOZY.
2. The plates are ALL EMPTY, so the serial and parallel rule can't be true.
3. The sum of the digits on T24JK1 is 7. That's not greater than 10, so that rule isn't true either.
4. However, because the battery count is TWO IN TWO, the number of D batteries is greater than the number of AA batteries.
5. That row, along with the color of the text on the screen being ORANGE, gives us TEIUQ as the 2nd part.
6. The serial number does not contain a vowel, so the two parts are swapped, giving TEUIQ BECOZY.
7. Are there strikes? No, the defuser and experts have been FLAWLESS. Don't add a 3rd part.
8. The sum of the serial number digits, 7, is prime. The whole key is reversed, giving us YZOCEBQUIET.
9. So the final matrix is:
10.  Y Z O C E B Q U I T A D F G H K L M N P R S V W X

### Step 2:

All of the clues hint at words from Playfair Cycle.

Each pair of words, (separated by a module), has another word "between" them. What this means is that the first word gives this word as a solution in a Playfair Cycle module, and the second word would be given as a solution by this word.

First word: "Inbetween" word: Second word:
ZIGZAGGY DISPATCH KILOBYTE
COMMANDO PROGRAMS JIGSAWED
UNDERRUN FINNICKY WINGSPAN
OCTONARY REVEALED ULTERIOR

The names of the modules between each pair of words fit into the meta categories. This allows us to associate these names with feeder answers. The feeder answer and the "inbetween" word its module corresponds to share 1 letter in the same position.

"Inbetween" word: Feeder: Module:
HOTLINKS FLAWLESS Poker (5 letter words)
DISPATCH TWO IN TWO Keypad (Words from Transmitted Morse)
PROGRAMS ORANGE Raiding Temples (Anagrams of community puzzle titles, with this one being an anagram of Departing Smile)
FINNICKY SPECIAL DAY Mahjong (Kudosudoku modules)
STOCKADE T24JK1 Geometry Dash (Video game titles)
REVEALED ALL EMPTY Pattern Cube (Words that contain Ice Cream names)

### Step 3:

The solution to a Playfair Cipher module with an orange screen and the decrypted word being STRIKE would be BADC.

The letters A, B, C, and D can be associated with numbers based on their position in the solution. However, since the position of the keys on a Playfair Cipher never change, the numbers can also be associated with directions, based on the positions of the keys.

Number: Direction:
1 Top-right (B)
2 Top-left (A)
3 Bottom-right (D)
4 Bottom-left (C)

A 2×2 grid is shown, each one containing a 5×5 grid of letters. The 4 quadrants correspond to keys on a Playfair Cipher.

Several coordinates are also provided below this grid. Each one consists of a number from 1 to 4 and a letter. For each coordinate, use the quadrant whose direction corresponds to the number, and then take the letter in that 5×5 matrix that is in the same position that the coordinate's letter is in in the Playfair matrix.

This gives us an encrypted message: QVTHPTKFNGICYVHS

Using the Playfair grid, this decrypts to USE THE MAGIC WORD. Do so to solve the puzzle.