Utilizing the provided musical theme and letter-based structure, compose a piece of music.
X:1
L:1/8
M:4/4
K:D
['DEFA B2 AB d2 cd BAFE D2']  
X:1
L:1/8
M:4/4
K:D
"D" DEFA B2 AB | d2 cd BAFE |"D" D2 DE FABA |"A7" c3 B AFEF |"D" D3 E FABA |"D" d3 B AFED | 
"C" =CDEC AGEC |"D" =C D2 C D4 ::"D" d4"A7" e4 |"D" fedB A4 |"D" f3 g fdAB |"C" =cBcd ed c2 | 
"D" d4"C" e4 |"D" faba fede |"D" fdAB"C" =cGEG |"A7" AFEC"D" D4 :|  