Craft a musical composition that adheres to the specified musical theme and letter-based structure.
X:1
L:1/8
M:2/4
K:D
['(3(ABc) d2', 'A2 (3(efg) a2 (fd) Tc2 dBBd c(e/c/)']  
X:1
L:1/8
M:2/4
K:D
|: (3(ABc) d2 | (BG) TF2 | GEEG | F(A/F/) DD | (3(ABc) d2 | ee/f/ g2 | (g/f/)e/d/ (c/B/)A/B/ | 
 B2 A2 :: (3(efg) a2 | (fd) Tc2 | dBBd | c(e/c/) AA | (3(ABc) d2 | (BG) TF2 | 
 (a/g/)f/e/ (d/c/)B/c/ | (cd) d2 :|  