Develop a musical piece incorporating the designated alphabet-based pattern and the supplied melodic theme.
X:1
L:1/16
M:2/4
K:G
['.vG2vDuC B,G,B,D ECFA', 'gfga bgdB cBcd']  
X:1
L:1/16
M:2/4
K:G
 uD2 | .vG2vDuC B,G,B,D | ECFA GFGA | BGFG .c2.B2 | AGFG .A2.D2 | .vG2vDuC B,G,B,D | ECFA GFGB | 
 BGcB AGFA | G2G2G2 :: ud2 | gfga bgdB | cBcd edcB | ABcd edcB | .A2{^c}d2{^c}d2{^c}d2 | 
 gfga bgdB | cBcd .e2.f2 | (gf).g.e (dB).G.c | (BG)(AF) G2 :|  