Develop a musical piece that combines the given theme and letter-structured outline.
X:1
L:1/4
Q:1/1=80
M:2/2
K:G
['G A']  
X:1
L:1/4
Q:1/1=80
M:2/2
K:G
 D | G A B G | A D c A | B d A c | B G G D | G A B G | A D c A | B d e f | g2 g |:  