Develop a musical piece using the given theme and incorporating the letter-based structure provided.
X:1
L:1/8
Q:1/4=120
M:4/4
K:F
['cB Af F2 F>dc>B A>cf>A B>gA>^f g>dg>a', '(3cde f2']  
X:1
L:1/8
Q:1/4=120
M:4/4
K:F
 cB | Af F2 F>dc>B | A>cf>A B>gA>^f | g>dg>a bagf | e2 c2 c2 de | f2 F2 f>ed>c | (3dba g>f e>dc>B | 
 A>fd>F E>dc>B | A2 F2 F2 :: (3cde | f2 (3fcA a2 (3afc | (3bge (3cAF EFGA | B2 (3gec (3bge (3cdA | 
 B2 A2 A2 (3cde | f2 F2 f>ed>c | (3dba g>f e>dc>B | A>fd>F E>dc>B | A2 F2 F2 :|  