Develop a musical piece that combines the given theme and letter-structured outline.
X:1
L:1/8
M:9/8
K:D
['a2 g fga def', 'd3 c2 d ecA gfe dcd faf']  
X:1
L:1/8
M:9/8
K:D
|: a2 g fga def | efg fed cBA | a2 g fga def | Bgf edc d3 :: c2 d ecA gfe | dcd faf e2 f | 
 gab agf edc | Bcd edA d3 :|  