Utilizing the provided musical theme and letter-based structure, compose a piece of music.
X:1
L:1/4
M:4/4
K:Gdor
['G2 G A B3 A G d', 'A4 G2 G A B3 A G', 'A4 d2 d d d3 c d', 'c4 c2 f e d3 c/B/ A']  
X:1
L:1/4
M:4/4
K:Gdor
 G2 G A | B3 A | G d c B | A4 || G2 G A | B3 A | G d c B | A4 || d2 d d | d3 c | d g e d | c4 || 
 c2 f e | d3 c/B/ | A G G ^F | G4 ||  