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:G
['G2 GF', 'GB B2 GBdB']  
X:1
L:1/8
M:4/4
K:G
 G2 GF GBdB | G2 BG A2 GE | G2 GF GABd | egdB AcBA :| GB B2 GBdB | GBdB A2 GE | GB B2 GBdB | 
 egdB A2 BA | GB B2 GBdB | GBdB A2 GE | G2 GF GABd | egdB AcBA ||  