Coding Pattern Identification

The problem involves a letter coding pattern. We need to find the rule used to transform words like 'CHILL' and 'HARSH' into their coded forms.

Analyzing 'CHILL' to 'HDNHQ'

• C (3rd letter) $\rightarrow$ H (8th letter): Difference is $8 - 3 = +5$
• H (8th letter) $\rightarrow$ D (4th letter): Difference is $4 - 8 = -4$
• I (9th letter) $\rightarrow$ N (14th letter): Difference is $14 - 9 = +5$
• L (12th letter) $\rightarrow$ H (8th letter): Difference is $8 - 12 = -4$
• L (12th letter) $\rightarrow$ Q (17th letter): Difference is $17 - 12 = +5$

The pattern observed is: +5, -4, +5, -4, +5.

Analyzing 'HARSH' to 'MWWOM'

• H (8th letter) $\rightarrow$ M (13th letter): $13 - 8 = +5$
• A (1st letter) $\rightarrow$ W (23rd letter): $23 - 1 = +22$. This is equivalent to $-4$ (since $1 - 4 = -3$, which corresponds to the 23rd letter, W, in a wrap-around manner).
• R (18th letter) $\rightarrow$ W (23rd letter): $23 - 18 = +5$
• S (19th letter) $\rightarrow$ O (15th letter): $15 - 19 = -4$
• H (8th letter) $\rightarrow$ M (13th letter): $13 - 8 = +5$

The pattern +5, -4, +5, -4, +5 is confirmed.

Applying the Pattern to 'DEVIL'

We apply the identified pattern (+5, -4, +5, -4, +5) to the letters of 'DEVIL':

• D (4th letter) + 5 = 9th letter $\rightarrow$ I
• E (5th letter) - 4 = 1st letter $\rightarrow$ A
• V (22nd letter) + 5 = 27th letter. Since there are 26 letters, the 27th letter is the 1st letter $\rightarrow$ A
• I (9th letter) - 4 = 5th letter $\rightarrow$ E
• L (12th letter) + 5 = 17th letter $\rightarrow$ Q

Therefore, 'DEVIL' will be written as 'IAAEQ'.