Construct a musical piece by amalgamating the designated alphabetical representation and the supplied musical theme.
X:1
L:1/8
M:4/4
K:Bb
['FGBd{d} e2 (eg)', '(gab)a (gf)ed cBcd']  
X:1
L:1/8
M:4/4
K:Bb
 FGBd{d} e2 (eg) | fdcB cBGB | FGBd{d} e2 (eg) | fdcd B/B/B B2 :| (gab)a (gf)ed | cBcd BGGf | 
 (gab)a (gf)ed | cBcd B/B/B B2 | gaba gfed | cBcd BGGB | FGBc defg | fdcd B/B/B B2 ||  