Develop a musical piece incorporating the designated alphabet-based pattern and the supplied melodic theme.
X:1
L:1/8
M:3/4
K:G
['(G/A/ Bc) (d/4c/4B/4c/4d/4e/4f/4g/4) (fdc>B) |{B} (AG/F/) (GDGA)', 'ga b2 ag (b/>a/)(a/g/) (fd) (de/f/) g>a']  
X:1
L:1/8
M:3/4
K:G
 (G/A/ Bc) | (d/4c/4B/4c/4d/4e/4f/4g/4) (fdc>B) |{B} (AG/F/) (GDGA) | (Bd) (c/A/G/F/) A>G | G3 :| 
 (de/f/) ga | b2 ag (b/>a/)(a/g/) | (fd) (de/f/) g>a | b2 (agba) | a3 (a/g/ fd) | 
 (f/g/a/g/) (fd) (cB) | (B/>A/G/F/) (GDGA) | (Bd) (c/A/G/F/) A>G | G3 ||  