Craft a piece of music that integrates both the suggested theme and letter-based structure.
X:1
L:1/8
Q:1/8=232
M:4/4
K:G
['ag fd ef']  
X:1
L:1/8
Q:1/8=232
M:4/4
K:G
|: c | d3 g BG dB | Aa ag fd ef | gf gd Bc dB | cA dc BG Gc | d3 g BG dB | Aa ag fd ef | 
 gf gd Bc dB | cA dc BG Gc | BG DG EG DG | AB cB ce dc | BG DG EG ce | dB cA BG Gc | BG DG EG DG | 
 AB cB ce dc | Bd gd ce ag | fd ef gG G :|  