Compose a piece of music by integrating the assigned letter representation and provided tune.
X:1
L:1/8
M:2/2
K:D
['FA A2 BAFA dfed', 'f2 af bfaf gfed']  
X:1
L:1/8
M:2/2
K:D
 FA A2 BAFA | dfed BcdB | FA A2 BAFA | dfed B2 AG | FA A2 BAFA | dfed Bdef | g3 e f3 e | 
 dfed B2 A2 :: f2 af bfaf | gfed Bcde | f2 af bfaf | gfed B2 A2 | f2 af bfaf | gfed Bdef | 
 g3 e f3 e | dfed B2 A2 :|  