Develop a musical composition based on the provided pattern of letters and incorporating the given motif within it.
X:1
L:1/8
M:6/8
K:Bb
['B2 d dBd', 'g fdB']  
X:1
L:1/8
M:6/8
K:Bb
|: B2 d dBd | A2 c cAc | B2 d dBd | f3 b3 | B2 d dBd | A2 c cAF | G/A/BG A/B/cA | G3 B3 :: 
 f2 g fdB | b2 g fdB | e2 g fdB | A3 c3 | D2 F FDF | B2 d cAF | G/A/BG A/B/cA | G3 B3 :|  