Craft a musical composition that adheres to the specified musical theme and letter-based structure.
X:1
L:1/8
Q:1/8=120
M:2/4
K:D
['d2 D>E FA AF/A/', 'd3 c/B/ Ad de d>c df e>d', 'EF/G/ Ad de d3 f e>d ef']  
X:1
L:1/8
Q:1/8=120
M:2/4
K:D
 B/c/ | d2 D>E | FA AF/A/ | BA/B/ cB | BA Bc | d2 D>E | FA AF/A/ | BB ce | d3 :| c/B/ | Ad de | 
 d>c df | e>d ef | d2 de | f>g fe | d>e dB | A>B AF | E2 EF/G/ || Ad de | d3 f | e>d ef | d2 fg | 
 a2 fd | B3 d/B/ | AA Bc | dc BA ||  