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:D
['A<F F>D', '(d/e/f/g/) a>g f<d d>f']  
X:1
L:1/8
Q:1/4=120
M:4/4
K:D
"^Strathspey." uB | A<F F>D E>D B,2 | A<F F>A B>cd>B | A<F F>D E>DE>F | D>B,A,>B, D2- D :: f | 
 (d/e/f/g/) a>g f<d d>f | a>df>d f<e e>f | (d/e/f/g/) a>g f<d d>f |1 d>B A<B d3 :|2 
 d/c/B/A/ B/d/c/e/ d3 |]  