Compose tunes based on the given letter-based musical structure and the supplied motif.
X:1
L:1/8
M:2/4
K:G
['GGGB G2 D2']  
X:1
L:1/8
M:2/4
K:G
 GGGB | G2 D2 | GGGB | G2 D2 | GG E2 | GGEE | GGAA | G2 E2 | GGGB | GG D2 | d>cBA | GG G2 |]  