Develop a musical composition based on the provided pattern of letters and incorporating the given motif within it.
X:1
L:1/4
Q:1/2=90
M:4/4
K:C
['G A2 G F', 'g g']  
X:1
L:1/4
Q:1/2=90
M:4/4
K:C
 c2 c/d/e/f/ | e e e d | c2 c/d/e/f/ | g G G G | A2 G F | E c2 G | A2 G F | E C3 :: g2 g/f/e/d/ | 
 c c c d | c G A _B | A F F2 | a2 a/g/^f/e/ | d d d e | d A B c | B2 A G | c2 c/d/e/^f/ | e e e d | 
 c2 c/d/e/f/ | g g g g | a2 g f | e g2 g | a2 g f | e c3 :|  