Develop a musical piece incorporating the designated alphabet-based pattern and the supplied melodic theme.
X:1
L:1/8
Q:1/4=62
M:4/4
K:F#min
['F2 c2 c2 (BA) (G3 F) (F2', 'c2 (cd) e2 (dc)']  
X:1
L:1/8
Q:1/4=62
M:4/4
K:F#min
"^Lento" F2 c2 c2 (BA) | (G3 F) (F2 ^E2) | F2 G2 A2 B2 | (c>Bcd c4) :| c2 (cd) e2 (dc) | 
 B2 (Bc) d2 c2 | c2 (cd) e2 (dc) | (B>c)(BA) G4 | (AB)(cd) c2 (BA) | (GABc) (B2 (AG) | 
 A2) GF c2 (BA) | (G3 F) F4 ||  