Compose tunes based on the given letter-based musical structure and the supplied motif.
X:1
L:1/8
M:2/4
K:G
['dBgB d{d}c/B/ c/e/A', 'a A2 e d/e/ d2 b', 'a/b/cd cdcb dcb bcba']  
X:1
L:1/8
M:2/4
K:G
 (B/c/) | dBgB | d{d}c/B/ c/e/A | cAac | e{e}d/^c/ d/g/B | dBgB | d{d}c/B/ c/e/A | cAaf | 
{a} g/f/g/a/ g :: (f/g/) | a A2 e | d/e/ d2 b | c/d/ c2 a | B/c/ B2 g | a A2 e | d/e/ d2 b | 
 c/d/c- ca | gbg!D.C.! :: d | d/e/f/g/ a/b/cd | cdcb dcb | bcba cb/a |{ab} ag b/a/g | 
 (d/e/)f/g/ a/b/cd | cdcb dcb | bcba cba | ggg!D.C.! :|  