Craft a piece of music that integrates both the suggested theme and letter-based structure.
X:1
L:1/8
Q:1/4=120
M:4/4
K:none
['', 'f<a a2', 'a>f d>f']  
X:1
L:1/8
Q:1/4=120
M:4/4
K:none
 A |: d2 c>d (3Bcd cA | B<g g>B cA A>g | f<a a2 a>g (3efg |1 f<a a2 a>f d>A :|2 f>d e>c d2 d || g | 
 f>d (3efg a>f d>f | g>B e>d cA A>g | a2 a>f d>f a>g | f>d e>d c<e (3efg | f>d (3efg a>f d>f | 
 g>B e>d c<e A>g | a2 a>f d>f a>g | f>d e>c d2 d |]  