Design a musical composition incorporating the alphabetic expression of the chosen structure and the provided melodic theme.
X:1
L:1/8
M:4/4
K:C
['A>c _BA G>F G', 'g>f eg']  
X:1
L:1/8
M:4/4
K:C
 F/G/ | A>c _BA G>F G A/=B/ | c>Bc/B/ G/E<FE/ CC/D/ | E>FG e/dc>B G/F/E/G/ | F>E CC C2 FG | 
 A>c _BA G>F G A/B/ | c>Bc/B/ G/E<FE/ C C/D/ | E>F G e/d/ c>B G/F/ E/G/ | F>E CC C2 || G/A/B/ | 
 c>d ef g>f eg | f>e fg f>e cG | c>d ef g>f eg | f>e cc c3 e/f/ | g>f eg f2 g/f/e/c/ | 
 _BG Bc/d/ e>f gE/F/ | G>F GA/B/ c>B GE/G/ | F>E CC C2 ||  