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
['G3 GAB GED AGE DEF G3', 'BGE DED']  
X:1
L:1/8
M:6/8
K:G
"A" |:"G" G3 GAB |"C" AGE"D" GED |"G" GFG"Am" AGE |"C" GED"D7" DEF |"G" G3 GAB |"C" AGE"G" GAB | 
"Am" cBA"Em" BGE |1"D" DED DEF :|2"D" DED D3"B" |:"C" cBA"G" BAG |"Am" ABA AGE |"C" cBA"G" BGE | 
"D7" DED D3 |"C" cBA"G" BAG |"Am" ABA ABc |"D7" dcA"C" GEA |"D" DED D3 :|  