Utilizing the provided musical theme and letter-based structure, compose a piece of music.
X:1
L:1/16
Q:1/4=100
M:2/4
K:D
['a2a2a2a2 a4 f2 z2 d4 e4 |{de}', 'fdfd a4', "B2d2e2f2 g2f2 efde c2c2d2e2 f2g2a2a2 (a2d'2)f'2f2 e2f2g2g2", 'B/A/G/F/) g/a/b/a/ g/f/e/d/ c/d/e/d/ c/B/A/G/ (FD)(AF) d4', "d4 .c'2.e'2 d4", 'FDFA FDFA GDGB GDGB GEGg decd BcAB']  
X:1
L:1/16
Q:1/4=100
M:2/4
K:D
 a2a2a2a2 | a4 f2 z2 | d4 e4 |{de} f4 z4 | g2g2g2g2 | g4 e2 z2 | c4 d4 |{cd} e4 z2 e2 || 
 (fd)(af) (d'c'ba) | (gaba) (gfge) | fdaf d'c'ba | gaba gfge | fdfd a4 | fdfd a4 | ecec g4 | 
 ecec g4 || f2e2 decd | B2d2e2f2 | g2f2 efde | c2c2d2e2 | f2g2a2a2 | (a2d'2)f'2f2 | e2f2g2g2 | 
 (g2c'2)e'2g2 |] (f/g/a/g/ f/e/d/c/) | (B/c/d/c/ B/A/G/F/) | g/a/b/a/ g/f/e/d/ | 
 c/d/e/d/ c/B/A/G/ | (FD)(AF) d4 | AFdA f4 | dAfd a4 | fdaf !fermata!d'4 || .g2.b2 d4 | .g2.b2 d4 | 
 .c'2.e'2 d4 | .c'2.e'2 d4 | .d'2.f'2 d4 | c'2d'2 g2b2 | abga fgef | decd BcAB || GDBG GDGB | 
 GDGB FDFA | FDFA | GDGB GDGB | GEGg | decd BcAB | G4 |]  