Compose a piece of music that follows both the given musical theme and the letter-based structure provided.
X:1
L:1/8
M:4/4
K:D
['BAFA DAFA BA (3Bcd e2 de fagf', 'fagf egfe']  
X:1
L:1/8
M:4/4
K:D
 DA | BAFA DAFA | BA (3Bcd e2 de | fagf egfe | de (3fed B2 dA | BAFA DAFA | BA (3Bcd e2 de | 
 fagf egfe | d2 dc d2 :: fg | afdf a2 gf | efga b2 ag | fagf egfe | de (3fed B2 dA | BAFA DAFA | 
 BA (3Bcd e2 de | fagf egfe | d2 d2 d2 :|  