Develop a musical piece incorporating the designated alphabet-based pattern and the supplied melodic theme.
X:1
L:1/4
Q:1/4=120
M:4/4
K:G
['B G/G/ A G B']  
X:1
L:1/4
Q:1/4=120
M:4/4
K:G
"G" B G/G/ A G | B G/G/ A G | B d d3/2 c/ | B G"D" A2 |"G" B G/G/ A G | B G/G/ A G | 
 B d"D" d3/2 c/ |"G" B G G2 ::"G" B2 B3/2 A/ |"C" G E E3/2 E/ |"G" D G G A |"D" B A A2 | 
"G" B2 B3/2 A/ |"C" G E E3/2 E/ |"D" D d d c |"G" B G G2 :|  