Design a musical composition incorporating the alphabetic expression of the chosen structure and the provided melodic theme.
X:1
L:1/8
M:6/8
K:A
['FAB c2 B BAc BAF c2 A', 'EFF AFF']  
X:1
L:1/8
M:6/8
K:A
 FAB c2 B | BAc BAF | c2 A BAF | ABB BAF | FAB c2 B | BAc BAF | c2 A BAF | EFF F3 :| EFF AFF | 
 BBc BAF | EFF AFF | c2 A BAF | EFF AFF | BBc BAF | c2 A BAF | EFF FFF :|  