Create a composition by utilizing the given alphabet-based musical pattern and the provided melodic theme.
X:1
L:1/4
M:3/4
K:C
['G/G/ G/G/']  
X:1
L:1/4
M:3/4
K:C
 G |"C" e d c | B A G |"G7" A G/G/ G/G/ | F z G | B G/G/ G/G/ | F z G |"C" c G/G/ G/G/ | E z G | 
 e d c | B A G |"G7" A G/G/ G/G/ | F z G | B G/G/ G/G/ | F G B |"C" c3/2 c/ c | c z z |]  