Construct a musical work following the provided guidelines and thematic elements.
X:1
L:1/8
M:2/4
K:G
['B G2 D', 'B A c c A G B'  
X:1
L:1/8
M:2/4
K:G
"^I" B | G2 D B | G2 D z | B B/ B/ A A/ A/ | G G D |"^I" B | G2 D B | G2 D z | B B/ B/ A A/ A/ | 
 G G G |]"^II" B | B d d B | A c c A | G B B G | F A A A | B d d B | A c c A | G B B G | F A G2 |]  