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 GABc dBeB dBAF', 'GB B2 eBdB']  
X:1
L:1/8
M:4/4
K:G
 D | G2 GF GABc | dBeB dBAF | D2 FD ADFD | DEFD AFEF | G2 GF GABc | dBeB dBAF | Be e2 dBAF | 
 DEFD E3 :| D | GB B2 eBdB | FA A2 AfdA | GB B2 eBdB | AGFG E3 F | GB B2 eBdB | FA A2 AfdA | 
 G2 GF GBdB | AGFG E3 :|  