Develop a musical piece that combines the given theme and letter-structured outline.
X:1
L:1/8
M:4/4
K:Amix
['a2 fa', '(3cBA eA']  
X:1
L:1/8
M:4/4
K:Amix
 a2 fa ecAB | (3cBA eA fAeA | a2 fa ecAc | Bcdc BGGA | a2 fa ecAB | cdef g2 fg | afge fdec | 
 Bcdc BG G2 :| (3cBA eA fAeA | (3cBA af ecAB | (3cBA eA fAec | Bcdc BGB=c | (3cBA eA fAed | 
 cdef g2 fg | afge fdec | Bcdc BG G2 :|  