Compose a piece of music that follows both the given musical theme and the letter-based structure provided.
X:1
L:1/8
M:6/8
K:C
['AAG AAG']  
X:1
L:1/8
M:6/8
K:C
 AAG AAG | AAG E2 (c/d/) | ee(d/c/) cA(c/A/) | GEG A2 (c/d/) | ee(c/c/) dd(e/d/) | 
 cA(G/E/) D2 (c/A/) | GEC DCD | EcG A3 |]  