Construct a music composition that complies with the designated structure and theme.
X:1
L:1/8
M:2/4
K:G
['BBAA G2']  
X:1
L:1/8
M:2/4
K:G
 B2 A2 | G2 DD/D/ | BBAA | G2 DD | BBAA | G2 D2 | DDDD | BBAA | G2 D2 |]  