Develop a musical piece incorporating the designated alphabet-based pattern and the supplied melodic theme.
X:1
L:1/8
M:6/8
K:D
['de^c dcA GFG AFD', 'D3 FED FGA =cdB cAG Afe de^c']  
X:1
L:1/8
M:6/8
K:D
 de^c dcA | GFG AFD | FEF GFD | FGA =c2 A | de^c dcA | GFG AFD | F3 GAG | FDD D3 :: FED FGA | 
 =cdB cAG | Afe de^c | AB^c d2 =c | B3 d=cA | GFG AFD | F3 GAG | FDD D3 :|  