Utilizing the provided musical theme and letter-based structure, compose a piece of music.
X:1
L:1/8
M:2/4
K:G
['G2 BA', 'f2 e2']  
X:1
L:1/8
M:2/4
K:G
 D2 | G2 BA B2 BA | GABc d2 ef | gfed edcB | cBAG GFED | G2 BA G2 BA | GABc d2 ef | gfed egfa | 
 gbaf g2 !fermata!x :: B2 | e2 ef g2 ga | b2 g2 f2 e2 | d2 de f2 fg | a2 f2 e2 d2 | e2 ef g2 ga | 
 b2 g2 f2 e2 | b^abc b=agf | e2 g2 e4"^D.C." :|  