Craft a piece of music that integrates both the suggested theme and letter-based structure.
X:1
L:1/8
M:4/4
K:D
['BAFA D2 FA BA (3Bcd e2 de', 'd2 fg afdf a2 af gfga b2']  
X:1
L:1/8
M:4/4
K:D
 FA | BAFA D2 FA | BA (3Bcd e2 de | faaf egfe | dfed B2 dB | BAFA D2 FA | BA (3Bcd e2 de | 
 faaf egfe | d2 dc d2 :| fg | afdf a2 af | gfga b2 ag | fagf egfe | dfed B2 dB | BAFA D2 FA | 
 BA (3Bcd e2 de | faaf egfe | d2 dc d2 :|  