Develop a musical piece using the given theme and incorporating the letter-based structure provided.
X:1
L:1/8
Q:3/8=120
M:6/8
K:D
['Bcd d2 A', 'A BGB']  
X:1
L:1/8
Q:3/8=120
M:6/8
K:D
 D | FGA FGA | Bcd d2 A | Bcd d2 A | BGE E2 D | FGA FGA | Bcd d2 A | Bcd d2 A | AFD D2 |: e | 
 f2 d ecA | faf ecA | Bcd d2 A | BGE E2 A | BGB AFA | GEG F2 A | BGB cAc | dAF D2"^*" :|  