Develop a musical piece using the given theme and incorporating the letter-based structure provided.
X:1
L:1/8
M:2/2
K:G
['DG{A}GF DG{A}GF F2 (AF) cFAF DG{A}GF DGGg', 'dfaf g2 bg dgbg agfa g2 (ga)']  
X:1
L:1/8
M:2/2
K:G
 DG{A}GF DG{A}GF | F2 (AF) cFAF | DG{A}GF DGGg |1 fdcA BGAF :|2 fdcA BG G2 || g2 bg dgbg | 
 f2 af dfaf | g2 bg dgbg | agfa g2 (ga) | bgaf gdde | fefd cAGF | dggf (3gab ag | fdcA BGAF |]  