Create musical compositions adhering to the given structure and incorporating the provided musical concept.
X:1
L:1/8
M:4/4
K:A
['e2 ef', 'a2 ga', 'c2 ca'  
X:1
L:1/8
M:4/4
K:A
 e2 ef edcd | e2 ef efga | e2 ef edcd | Bcde f2 ef :| a2 ga fece | a2 ga f2 ef | a2 ga fedc | 
 Bcde f2 ef | a2 ga fece | a2 ga f2 ef | agae fedc | Bcde f2 ed |: c2 ca c2 ca | c2 a2 fedc | 
 c2 ca c2 ca |1 Bcde f2 ed :|2 Bcde f2 ef ||  