Compose tunes based on the given letter-based musical structure and the supplied motif.
X:1
L:1/8
Q:1/4=160
M:6/8
K:G
['B2 B', 'A2 A', 'd2 d']  
X:1
L:1/8
Q:1/4=160
M:6/8
K:G
 B2 B B2 B | ABA G2 G | F2 G A2 F | G2 A B3 | B2 B B2 B | ABA GAB | c2 B A2 G | FEF G3 :: 
[K:D] A2 A F2 D | GAB A3 | A2 A F2 D | GAB A2 A | d2 d c2 c | B2 B A2 A | G2 G F2 F | EDE D3 :: 
[K:G] d2 d d2 d | cdc B2 B | A2 B c2 A | B2 c d3 | d2 d d2 d | cdc Bcd | e2 d c2 B | AGF G3 :|  