Develop a musical piece using the given theme and incorporating the letter-based structure provided.
X:1
L:1/8
Q:1/2=90
M:2/2
K:G
['d4 g4 f6 ed e2 d2 e2', 'd2 d2']  
X:1
L:1/8
Q:1/2=90
M:2/2
K:G
 d4 g4 | f6 ed | e2 d2 e2 dc | d2 B2 d2 cB | c2 A2 c2 BA | B3 c Bc d2 | G2 c2 B3 A | A8 || 
 A3 B AB c2 | B6 cB | A2 BA GBAG | F4 BcBA | G4 ABAG | F2 AB cB AG | F3 G F2 B2 | G3 F E2 e2 | 
 BcBc d2 d2 | d2 cB c2 c2 | c2 BA Bc d2 | GcBA A3 G | G8 |]  