Craft a musical composition that adheres to the specified musical theme and letter-based structure.
X:1
L:1/8
Q:1/4=120
M:3/8
K:G
['d/c/Bc d2 e', 'A/B/cB A2 d d/c/BA']  
X:1
L:1/8
Q:1/4=120
M:3/8
K:G
 d | d/c/Bc | d2 e | d/c/BA | BGd | d/c/Bc | d2 e | d/c/BA | G2 :| G | A/B/cB | A2 d | d/c/BA | 
 BGd | A/B/cB | A2 d | d/c/BA | G2 :|  