Develop a musical piece using the given theme and incorporating the letter-based structure provided.
X:1
L:1/4
M:3/2
K:G
['c B A']  
X:1
L:1/4
M:3/2
K:G
 D | G D G2 d2 | c A F D z A/B/ | c c B A G E | F G A2 A3/2 B/ |"^(a)" c/d/e/d/ d2 G3/2 A/ | 
 B A/G/ G2 !fermata!D A/G/ | E D G B d c | B A G3 |]  