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:Bdor
['[K:F#dor]|:{AB} c2', 'AFFE CFFG', 'agfa |{ga}']  
X:1
L:1/8
M:4/4
K:Bdor
[K:F#dor]|:{AB} c2 c{=dc}B AFFE | CFFG AecB |{AB} c2 c{dc}B AFFd | eEEG BAGE | 
{AB} c2 c{=dc}B AFFE | CFFG ABcd | d!fermata!eBe dfBd | e/f/g Be GBEG :: Fffg{gg} agf{gf}e | 
 !fermata!cAAB ABcA | Fffg{ggag} agfa |{ga} bag{ag}f eEGE | Fffg{fg} agfa |{ga} gfed egbg | 
 fgaTf ecBA | GABc A/G/F GE :|  