Develop a musical piece that combines the given theme and letter-structured outline.
X:1
L:1/8
M:6/8
K:G
['d2 B', 'ABc def gfg def gab']  
X:1
L:1/8
M:6/8
K:G
|: d2 B dBG | d2 B dge | d2 B dBG | ABG ABc | d2 B dBG | d2 B dge | def gdB | ABG ABc :: def gfg | 
 def gab | def gdB | ABG ABc | def gfg | def gab | c'af gdB | A2 G ABc :|  