Develop a musical piece using the given theme and incorporating the letter-based structure provided.
X:1
L:1/8
Q:1/8=320
M:2/4
K:G
['G>A BG', 'Ec c>G Ec GE']  
X:1
L:1/8
Q:1/8=320
M:2/4
K:G
 G>A BG | cB cA | G>A BG | FA FD | G>A BG | cB cA | Bd c/B/A/G/ | FA FD :: Ec c>G | Ec GE | 
 F/A/d d>A | Fd AF | Ec c>G | Ec GE | Bd c/B/A/G/ | FA FD :|  