Develop a musical piece using the given theme and incorporating the letter-based structure provided.
X:1
L:1/8
M:4/4
K:C
['AEED CEAB cdBc A2 Bc BG G2', 'eA A2']  
X:1
L:1/8
M:4/4
K:C
|: B | AEED CEAB | cdBc A2 Bc | BG G2 Bcdf | edcB cBAG | AEED CEAB | cdBc A2 Bc | BG G2 Bcdf | 
 edcB A3 :: =f | eA A2 eAgA | ^fd d2 fdad | eA A2 eAge | dBGB d2 e=f | eA A2 eAgA | ^fd d2 fdad | 
 eA A2 eAge | dBGB A3 :|  