Develop a musical piece that combines the given theme and letter-structured outline.
X:1
L:1/8
Q:1/8=120
M:2/4
K:G
['D>E DB, D>E GA Bd', '', 'ge fd', 'GA Bd AB G2 G C: 2nd', 'fg/f/ ef/e/ dD FA', 'BDBD B/A/B/c/ ed cA f/g/a/f/']  
X:1
L:1/8
Q:1/8=120
M:2/4
K:G
"^Part A" D>E DB, | D>E GA | Bd AB/A/ | GE EG/E/ | D>E DB, | D>E GA | Bd A>B |1 
 G/D/G/A/ B/d/g/e/ :|2 G2 G z ||"^final" G4 |]"^Part B: 1st & 3rd" Bd dB | cee z | Bd AB/A/ | 
 GE ED | Bd d>B | ce e>f | ge fd |1 e/g/f/e/ d/e/d/c/ :|2 e3 e/f/ || ge fd | e/f/e/d/ BA | 
 Bd AB/A/ | GE EG/E/ | D>E DB, | D>E GA | Bd AB | G2 G ||"^Part C: 2nd & 4th" d/c/ | BDBD | 
 B/A/B/c/ ed | cA f/g/a/f/ | gg g/e/d/c/ | BDBD | B/A/B/c/ ed | cA f/g/a/f/ | ggg z || 
[K:D] fg/f/ ef/e/ | dD FA | Bc/B/ Aa/g/ | fg/f/e z | fg/f/ ef/e/ | dD FA | Bc/B/ Af/e/ | 
 dd d/e/d/=c/ ||[K:G] BDBD | B/A/B/c/ ed | cA f/g/a/f/ | gg g/e/d/c/ | BDBD | B/A/B/c/ ed | 
 cA f/g/a/f/ | ggg z ||  