Develop a musical composition using the outlined alphabetical depiction of the structure and the provided theme.
X:1
L:1/8
M:4/4
K:G
['Bc dBGB AGEG dGBG c2 ce dGBG', 'fdd=f ecce dBcA']  
X:1
L:1/8
M:4/4
K:G
 Bc | dBGB AGEG | dGBG c2 ce | dGBG AGEG | dBcA G2 || AG | Ad de =fefd | dgg^f g2 ag | fdd=f ecce | 
 dBcA G2 AG | Adde =fefd | dgg=f gbag | fdd=f ecce | dBcA G2 ||  