Develop a musical piece using the given theme and incorporating the letter-based structure provided.
X:1
L:1/8
M:2/4
K:D
['F3 F F3 ^G/A/ F3 F/>A/ ||[M:3/4]', 'F/G/F/E/ D>E D2', 'B,6 B,B, B,B, B,F, ||[M:2/4] B,3 C/D/', 'A, F,F, F,F, E,B,, [M:2/4]', 'G,/F,/ E,4', '']  
X:1
L:1/8
M:2/4
K:D
 F3 F | F3 ^G/A/ | F3 F/>A/ ||[M:3/4] FF FE B,2 ||[M:2/4] F2 F/G/F/E/ | D>E D2 ||[M:3/4] B,6 | 
 B,B, B,B, B,F, ||[M:2/4] B,3 C/D/ | B,3 A,[K:bass] ||[M:3/4] F,4 z A, | F,F, F,F, E,B,, || 
[M:2/4] F,3 G,/F,/ | E,4 | D,B,,- B,,2- | B,,4 |]  