Write a musical work incorporating the specified theme and letter-based framework.
X:1
L:1/8
Q:1/4=140
M:2/4
K:F
['F2 Ac G2 Bd', 'AF Ac BG Bd']  
X:1
L:1/8
Q:1/4=140
M:2/4
K:F
 F2 Ac | G2 Bd | cf ed | cB AG | F2 Ac | G2 Bd | cB AG | F2 F2 :| f2 fa | g2 fe | fe dc | =B2 AG | 
 c2 eg | d2 fa | gf ed | cd cB | AF Ac | BG Bd | cf ed | cB AG | AF Ac | BG Bd | cB AG | F2 F2 |]  