Craft a composition that integrates the assigned alphabet-related musical pattern and the provided melodic theme.
X:1
L:1/8
M:2/4
K:G
['.G.D.G.B .G.D.G.B', 'G2 d2 B2 G3 D GDGB BA']  
X:1
L:1/8
M:2/4
K:G
 .G.D.G.B | .G.D.G.B | .G.D.G.B | .B.A A2 | FDFA | FDFA | FDFA | AG G2 :| d2 B2 | G3 D | GDGB | 
 BA A2 | c2 A2 | F3 D | FDFA | AG G2 :|  