Craft a musical composition that adheres to the specified musical theme and letter-based structure.
X:1
L:1/8
M:6/8
K:A
['fga gee efg aba aec ecA dBe']  
X:1
L:1/8
M:6/8
K:A
|:"A" Ace aga |"D" fed"E7" cdB |"A" Ace"B7" fga |"E7" gee efg |"A" aba aec |"D" dfa"A" ecA | 
"^(F#m)" ABc"E7" dBe |"^(A)" cAG"A" A3 ::"A" ece"D" fdf |"A" ecA"E7" B2 c |"A" Ace"B7" fga | 
"E7" gee efg |"A" aba aec |"D" dfa"A" ecA |"^(F#m)" Ace"E7" dBe |"^(A)" cAG"A" A3 :|  