Craft a musical composition that adheres to the specified musical theme and letter-based structure.
X:1
L:1/8
M:2/4
K:G
['', '[Bd][Bd] [ce][d=f] [ce][Bd] d c2 B B', 'cB B A2 G G2 BB BA', 'G BB BA A G2 G AB', 'G(B B)B AG', '^F(A A)A G^F G2 D(G G)']  
X:1
L:1/8
M:2/4
K:G
"A" |:"G" [Bd][Bd] [Bd][Bd] | [ce][d=f] [ce][Bd] | d c2 B |"D7" d/c/B/c/"G" B :|[K:Gmin]"B" |: 
"Gm" [GB][GB] [GB][GB] | ^cd cB | B A2 G |"D7" B/A/G/^F/"Gm" G2 :|"C" |:"Gm" BB BA |"Eb" A G2 G | 
"Gm" BB BA |"Eb" A G2 G |"Gm" AB cB |"D7" _d c2 B |"Gm" (3=dcB (3BAG | [GB]G AB :|"D" |: 
"Cm" c2 G(c | c)c BA |"Gm" B2 G(B | B)B AG |"D7" A2 ^F(A | A)A G^F |"Gm" G2 D(G | G) z3 :|  