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:Gmin
['.G .d']  
X:1
L:1/4
Q:1/4=120
M:4/4
K:Gmin
"Gm" .G .d .B .G |"Dm" F/G/ G/F/"Gm" B A | .G .d .B .G |"Dm" F/G/ G/F/"Gm" G2 |"Gm" .G .d B/A/ G | 
"Dm" F/G/ G/F/"Gm" B/A/ G | .G .d .B .G |"Dm" A/G/ G/F/"Gm" G2 |:"Dm" F/G/A/B/"F" c d | c B c z | 
"Dm" F/G/A/B/"Gm" d c |1 B A G z :|  