Utilizing the provided musical theme and letter-based structure, compose a piece of music.
X:1
L:1/8
M:3/4
K:G
['B3 A G2 d4 AB c2 cd', 'Bc BA GB dD FG AB cd']  
X:1
L:1/8
M:3/4
K:G
 B3 A G2 | d4 AB | c2 cd e2 | d5 | g4 B2 | A4 GA | G2 E2 D2 | D2 d2 c2 | B3 A G2 | d4 AB | 
 c2 cd e2 | d5 | g4 B2 | A4 GA | G5 || Bc BA GB | dD FG AB | cd eg fe | d5 | gB Bg fe | AB dc BA | 
 G2 E2 D2 | D2 d2 c2 | Bc BA GB | dD FG AB | cd eg fe | d5 | gB Bg fe | AB dc BA | G5 ||  