Craft a musical piece that abides by the prescribed structural guidelines and the given theme.
X:1
L:1/8
M:6/8
K:G
['A2 F FEF G2 G B2 B', 'G2 G c2 c BAG'  
X:1
L:1/8
M:6/8
K:G
 A2 F FEF | G2 G B2 B | BAG F3 | A2 F FEF | G2 G B2 B | BAG F3 || G2 G c2 c | BAG FGA | G2 G c2 c | 
 BAG FGA :|  