Assemble a piece of music by merging the alphabetic representation of the predetermined musical pattern and the provided melodic theme.
X:1
L:1/8
M:2/4
K:G
['GABc eddd cBAd B2']  
X:1
L:1/8
M:2/4
K:G
 D | GABc | eddd | cBAd | B2 GD | GABc | eddd | cBAd | B2 GG | AABB | ccdd | AABG | d2 DD | GABc | 
 eddd | cBAd | B2 G |]  