Compose a musical piece using the designated musical pattern's alphabetic representation and the assigned melodic theme.
X:1
L:1/4
M:3/4
K:F
['F _A']  
X:1
L:1/4
M:3/4
K:F
 F | F _A | c2 d | c B/_A/ | G2 F | _A B | c2 B/_A/ | G2 | F2 F | F G | _A G F | _E/E/ F | G2 F | 
 _A B | c2 B/_A/ | G2 | F2 |]  