Compose a piece of music that follows both the given musical theme and the letter-based structure provided.
X:1
L:1/8
Q:3/8=100
M:6/8
K:G
['D G2 A BGB A3 c3 Bcd', 'B Bcd']  
X:1
L:1/8
Q:3/8=100
M:6/8
K:G
 D | G2 A BGB | A3 c3 | Bcd ABc | G2 D D2 D | G2 A BGB | A3 c3 | Bcd Ad^c | d3- d2 :: d | 
 e2 c cde | d2 B Bcd | c2 A ABc | B2 D D2 A | B2 B Bcd | A2 A ABc | Bcd AGF | G3- G2 :|  