Craft a musical composition that adheres to the specified musical theme and letter-based structure.
X:1
L:1/8
Q:1/8=160
M:6/8
K:D
['d2 f agf', 'd AGF', 'F G2', 'E2 F']  
X:1
L:1/8
Q:1/8=160
M:6/8
K:D
 e | d2 f agf | agf a2 f | d2 f agf | e2 f g2 e |"^5" d2 f agf | agf a2 f | gbg faf | e2 f g2 :: 
 e |"^9" fed dAF | DFA dAd | fed dAd | e2 f g2 e |"^13" fed dAF | DED dAF | G2 d AGF | E2 F G2 :: 
 E |"^17" D2 d AGF | AGF AGF | D2 d AGF | E2 F G2 E |"^21" D2 d AGF | AGF A2 F | G2 d AGF | 
 E2 F G2 :: e |"^25" d3 cBc | dAF FED | d3 cBc | e2 f g2 e |"^29" dfd cec | dAF FED | G2 d AGF |1 
 E2 F G2 :|2 E2 F GFE | D6 |]  