Develop tuneful melodies adhering to the specified letter notation and including the supplied thematic aspect.
X:1
L:1/4
M:2/2
K:Dmix
['d e f g', 'd e f g']  
X:1
L:1/4
M:2/2
K:Dmix
 d | e f g e | f/e/f/g/ f d | e f g e | f3 :: d | e f g f | e3 d | c B c d | e/d/e/f/ e d | 
 e f g a/g/ | f2 e a/g/ | f/e/ f e3/2 d/ | d3 :|  