Compose a piece of music that follows both the given musical theme and the letter-based structure provided.
X:1
L:1/8
Q:1/2=60
M:2/4
K:C
['EGGB c/B/c/d/ ef', 'd/c/d/e/ dg', 'e f_AGe f_AGe dd (d/c/B/A/)']  
X:1
L:1/8
Q:1/2=60
M:2/4
K:C
 G/F/ | EGGB | c/B/c/d/ ef | gcgG | A2 GF | EGGB | c/B/c/d/ ef | gcdB | c2 z || !fermata!d | dcdc | 
 d/c/d/e/ dg | fa c'c' | b2 gf | dcBc | d/c/d/e/ dg | ^fc'af | g2 zS || e | f_AGe | f_AGe | 
 dd (d/c/B/A/) | G2 z e | f_AGe | f_AGe | dd (d/c/B/A/) | G3S |]  