If in a certain code, CLQYB is written as EIUTH, then how would TPRHA be…

Concept: In an alternating letter-shift code, each letter of a word moves along the alphabet by a value from a repeating signed sequence (e.g. +2, -3, +4, -5, +6), one shift per letter position. Once this shift sequence is derived from one code pair, the same sequence, applied in the same order, encodes any other word.

Deriving the shift sequence from CLQYB to EIUTH, letter by letter:

1. C (3rd letter) moves to E (5th letter): a shift of +2.

2. L (12th letter) moves to I (9th letter): a shift of -3.

3. Q (17th letter) moves to U (21st letter): a shift of +4.

4. Y (25th letter) moves to T (20th letter): a shift of -5.

5. B (2nd letter) moves to H (8th letter): a shift of +6.

So the recurring shift sequence, applied position by position, is +2, -3, +4, -5, +6.

Applying this same sequence, in the same order, to the letters of TPRHA:

1. T shifted by +2 gives V.

2. P shifted by -3 gives M.

3. R shifted by +4 gives V.

4. H shifted by -5 gives C.

5. A shifted by +6 gives G.

Reading the shifted letters in order gives the code VMVCG.

Cross-check: reversing the same sequence (-2, +3, -4, +5, -6) on VMVCG regenerates T, P, R, H, A, confirming the shift sequence is applied consistently in both directions.