Develop a musical piece incorporating the designated alphabet-based pattern and the supplied melodic theme.
X:1
L:1/8
Q:1/4=170
M:6/8
K:F
['F2 G A2 A B2 A F2', 'B3 A2 A ABA G2 G G3']  
X:1
L:1/8
Q:1/4=170
M:6/8
K:F
 F2 G A2 A | B2 A F2 F | c2 B ABc | F3 F2 c | c2 c d2 c | B2 B B3 |: A2 A ABA | G2 G G3 | 
 c2 B ABc |1 A3 A3 :|2 F6 ||  