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:Gdor
['DGGA B2 cB', 'b2 ag']  
X:1
L:1/8
M:2/2
K:Gdor
 DGGA B2 cB | AFcF dFcF | DGGA B2 cB | Acfc AGGF | DGGA B2 cB | AF F2 dFcF | DGGA B2 cB | 
 Acfc AGGF || Ggga b2 ag | fcac gcfc | dgga b2 ag | fdcA B2 AF | Ggga bgag | f3 g agfa | 
 g2 fg dfcd | AFcA BGGF ||  