Craft a piece of music that integrates both the suggested theme and letter-based structure.
X:1
L:1/16
M:2/4
K:D
['A2A2 A2A2 ABAG F2A2 BGBd cABc', 'a4 a2b2']  
X:1
L:1/16
M:2/4
K:D
 FG | A2A2 A2A2 | ABAG F2A2 | BGBd cABc | d2d2 defd | A2A2 A2A2 | ABAG F2A2 | BGBd cABc | d4 z2 :: 
 fg | a4 a2b2 | b2a2f2a2 | b2a2f2d2 | edef efge | a4 a2b2 | b2a2 f4 | a2f2 edef | c4 z2 :|  