Craft a musical composition that adheres to the specified musical theme and letter-based structure.
X:1
L:1/8
M:6/8
K:G
['Bcd g2 d d2 c']  
X:1
L:1/8
M:6/8
K:G
|: D |"G" GDG BAG |"C" ECE"D7" D2 c |"G" BAG"G/B" dBG |"D" FAA"D7/F#" ABc |"G" BAB"Em" GFG | 
"C" ECE"D7" D2 c |"G" BAG"D7" FGA |"Cm/G" AGG"G" G2 :| d |"G" Bcd g2 d |"C" ece"D7" d2 c | 
"G" BAG"G/B" dBG |"D" FAA"D7/F#" A2 c |"G" Bcd g2 d |"C" ece"D7" d2 c |"G" BAG"D7" FGA | 
"Cm/G" AGG"G" G2 d |"G" Bcd g2 d |"C" ece"D7" d2 c |"G" BAG"G/B" dBG |"D" FAA"D7/F#" ABc | 
"G" BAB"Em" GFG |"C" ECE"D7" D2 c |"G" BAG"D7" FGA |"Cm/G" AGG"G" G2 :|  