Design a musical composition incorporating the alphabetic expression of the chosen structure and the provided melodic theme.
X:1
L:1/8
Q:1/4=130
M:2/4
K:C
['G2 c>d cB d2 G2 d>e dc']  
X:1
L:1/8
Q:1/4=130
M:2/4
K:C
 G2 c>d | cB d2 | G2 d>e | dc e2 | G2 cd | e^de^f | gb^gb | e z g2 | g2 c'd' | c'b d'2 | 
"^Pia" g2 d'e' | d'c' e'2 | gc'bb | ^gaba | g>G e>d | c z c' z |]  