Develop a musical composition based on the provided pattern of letters and incorporating the given motif within it.
X:1
L:1/8
Q:3/8=110
M:6/8
K:G
['BBB BBB B2 A GAB ccc c2', 'gfe ddd d2 e d2 c Bdg']  
X:1
L:1/8
Q:3/8=110
M:6/8
K:G
|: BBB BBB | B2 A GAB | ccc c2 B | c2 d efg | fff fff | fed cBA |1 GBd e2 d | B3 Bdc :|2 GBd g2 a | 
 g3 d2 g || bbb bbb | b2 a gfe | ddd d2 e | d2 c Bdg | fff fff | fed cBA |1 GBd e2 d | B3 Bdg :|  