Compose a piece of music that follows both the given musical theme and the letter-based structure provided.
X:1
L:1/8
M:2/2
K:D
['g2 ag', 'G A2 F2 G2 BB dBAF D3']  
X:1
L:1/8
M:2/2
K:D
 d>d d2 Ac | defa g2 ag | f2 af edcA | d2 ef g2 ag | fdec d2 Ac | defa g2 ag | fgaf edcA | 
 [Fd]2 ef g2 ag |[M:3/4] fdec d2 ||[M:2/2] A2 F2 G2 BG | ABAF E3 G | A2 F2 G2 BB | dBAF D3 A- | 
 ABAF G2 [GB]2 | ABA[FA] [EA]3 A- | AF G2 B2 |[M:3/4] dBAF D ||  