LEAF becomes PHCG :

• L becomes P -> +4
• E becomes H -> +3
• A becomes C -> +2
• F becomes G -> +1

Each letter is shifted forward by a decreasing amount (4, 3, 2, 1).

Let's apply the reverse to WSQU:

• W becomes S -> -4
• S becomes P -> -3
• Q becomes O -> -2
• U becomes T -> -1

Therefore, WSQU means SPOT.

SMART becomes TODVY Explanation:

• S becomes T -> +1
• M becomes O -> +2
• A becomes D -> +3
• R becomes V -> +4
• T becomes Y -> +5

The code uses an incrementing shift: +1, -2, +3, +4, +5.

Applying the same pattern to TREND:

• T becomes U -> +1
• R becomes T -> +2
• E becomes H -> +3
• N becomes R -> +4
• D becomes I -> +5

Therefore, the code for TREND is UTHRI.

CHAT becomes ZEXQ

• C becomes Z -> -2
• H becomes E -> -2
• A becomes X -> -2
• T becomes Q -> -2

let's apply the reverse to IDFW:

• I + 2 -> F
• D + 2 -> A
• F + 2 -> C
• W + 2 -> T

Therefore IDFW means FACT

MUSIC is NWVMH

• M becomes N -> +1
• U becomes W -> +2
• S becomes V -> +3
• I becomes M -> +4
• C becomes H -> +5

let's apply this to PIANO:

• P becomes Q -> +1
  I becomes K -> +2
  A becomes D -> +3
  N becomes R -> +4
  O becomes T -> +5

  Therefore, the code for PIANO is QKDRT

FRUIT becomes AMPDO:

F becomes A -> -5
R becomes M -> -5
U becomes P -> -5
I becomes D -> -5
T becomes O -> -5

Each letter is shifted back 5 positions in the alphabet.

Let's apply this to HEART:

H becomes C -> -5
E becomes Z -> -5 (wrap around)
A becomes V -> -5 (wrap around)
R becomes M -> -5
T becomes O -> -5

Therefore, the code for HEART is CZVMO.

ONLY is LKIV, what does YLXQ mean?

• O becomes L -> -2
• N becomes K -> -2
• L becomes I -> -2
• Y becomes V -> -2

let's apply the reverse to YLXQ:

• Y + 2 -> B
• L + 2 -> O
• X + 2 -> A
• Q + 2 -> T

Therefore YLXQ means BOAT

A   B   C   D   E   F   G    H   I   J   K   L   M   N   O   P   Q   R   S   T   U   V   W   X   Y   Z

T - S        ->   G - F
O * H       ->  R * P
K ** M     ->  A ** X
E *** A     -> P *** L
N **** I   ->  E **** Z