Utilizing the provided musical theme and letter-based structure, compose a piece of music.
X:1
L:1/8
Q:1/4=70
M:2/4
K:G
['z D/D/']  
X:1
L:1/8
Q:1/4=70
M:2/4
K:G
 D/D/ |"G" DB BB |"C" BA EG |"D7" GF ED |"G" D2 z D/D/ |"D7" DF FA |"G" AG GB |"A7" BA EA | 
"D" A2 z D/D/ |"D7" Dc cc |"G" cB BB |"B" BF"Em" GA |"B" B2 z B/B/ |"G" Bd"G7" dd |"C" dc GA | 
"Gm" _BB"Bb7" BB |"Eb" !fermata!_B2 =AG |"G/D" D>D"D7" DD |"G" D2 z |]  