Craft a piece of music that integrates both the suggested theme and letter-based structure.
X:1
L:1/8
M:4/4
K:D
['ACeC ACeC', 'eaa ebb ebb eaa eaa']  
X:1
L:1/8
M:4/4
K:D
 ACeC ACeC | ACeC dBgB | ACeC ACeC | ACeC gfedBGG :|[M:6/8] eaa eaa | ebb ebb | eaa eaa | 
 gfedBGG :|  