Compose a piece of music by integrating the assigned letter representation and provided tune.
X:1
L:1/8
M:2/4
K:D
['Ad fa ge e2 cd ef', 'd2 fa af/a/ ba gf eg ge/g/']  
X:1
L:1/8
M:2/4
K:D
|: Ad fa | ge e2 | cd ef | d2 d2 | Ad fa | ge e2 | cd ef | d2 d2 :: fa af/a/ | ba gf | eg ge/g/ | 
 ag fe | df fd/f/ | gf ed | cd ef | d2 d2 :|  