Craft a musical composition that adheres to the specified musical theme and letter-based structure.
X:1
L:1/8
M:6/8
K:D
['DFA B2 A def g2 e fdf', 'agf eg=c eg=c egg gfe fef gfg']  
X:1
L:1/8
M:6/8
K:D
 DFA B2 A | def g2 e | fdf ecA | BdB AFE | DFA B2 A | def g2 e | fdf ecA |1 Bdc dAF :|2 Bdc d2 e |: 
 fad fad | faa agf | eg=c eg=c | egg gfe | fef gfg | agf efg | fed =cAG |1 Ad^c d2 e :|2 
 Ad^c dAF ||  