Craft a musical composition that adheres to the specified musical theme and letter-based structure.
X:1
L:1/4
M:2/2
K:G
['d/c/B/A/ B G', 'g f/e/']  
X:1
L:1/4
M:2/2
K:G
 G A | B c d/c/B/A/ | B G d g | d B/c/ d/c/B/A/ | B G G A | B c d/c/B/A/ | B G d g | 
 d B/c/ d/c/B/A/ | G2 ::"^2f" d e/f/ | g f/e/ d c | !plus!B2 d c/B/ | A G !plus!F G | 
 d D g !plus!f | g d g !plus!f | g2 G A | !plus!B c d/c/B/A/ | B G G A | !plus!B c d/c/B/A/ | 
 G e/f/ g f/e/ | d e/f/ g f/e/ | d2 g f/e/ | d G A !plus!F | G2 :|  