Compose a piece of music that follows both the given musical theme and the letter-based structure provided.
X:1
L:1/8
Q:1/4=72
M:3/4
K:C
['BA G z Ac']  
X:1
L:1/8
Q:1/4=72
M:3/4
K:C
 c z c z cB/A/ | BA G z Ac | BA G z Ac | B A G2 z2 | c z c z cB/A/ | BA G z Ac | BA G z Ac | 
 GF/E/ F z E2 |[M:2/4] D C3 | F z AF |[M:3/4] GF/E/ F z E2 |[M:2/4] D C3 |]  