Develop a musical composition using the outlined alphabetical depiction of the structure and the provided theme.
X:1
L:1/8
Q:1/8=240
M:6/8
K:G
['efg dBd']  
X:1
L:1/8
Q:1/8=240
M:6/8
K:G
"G" GBd eBd |"Em" efg dBd |"G" GBd eBd |"D" e2 f"G" g3 |"G" GBd eBd |"Em" efg dBd |"G" bag agf | 
"D" e2 f"G" g3 ::"G" bag agf |"Em" efg dBd |"G" bag agf |"Em" e2 a"D" a3 |"G" bag agf | 
"Em" efg dBd |"G" G3 dBd |"D" e2 f"G" g3 :|  