Create a musical composition adhering to the provided thematic and alphabetical guidelines.
X:1
L:1/8
Q:1/2=100
M:4/4
K:Amix
['dfaf bgaf', 'dfBf dfBf']  
X:1
L:1/8
Q:1/2=100
M:4/4
K:Amix
 dfaf bgaf | dfaf ecAc | dfaf bgaf | bgaf ecAc :| dfBf dfBf | dfBf ecAc | dfBf dfBf | bgaf ecAc :|  