Craft a musical composition that adheres to the specified musical theme and letter-based structure.
X:1
L:1/8
Q:3/8=120
M:6/8
K:F
['d c3 AcA', 'cBA G2 A B2']  
X:1
L:1/8
Q:3/8=120
M:6/8
K:F
|: d | c3 AcA | F2 A B2 d | c3 AcA | G2 A B2 d | c3 AcA | F2 A cde | fed cBA | G2 A B2 d || 
 faf cAc | faf cAc | faf cBA | G2 A B2 d | faf gbg | agf edc | fed cBA | G2 A B2 d |]  