Develop a musical piece using the given theme and incorporating the letter-based structure provided.
X:1
L:1/8
Q:1/8=320
M:6/8
K:G
['A2 F B2 F', 'GFE d>fg', 'd2 e', 'def def', 'D3 D3', '[fB]3 BAG FED']  
X:1
L:1/8
Q:1/8=320
M:6/8
K:G
"^A" A2 F B2 F | A2 G FED | A2 F B2 F | G>AG GFE | A2 F B2 F | A2 G FED | G2 B cAF | G>AG GFE :| 
"^B"S d>fg age | d^cd ecA | G>AB cAF | G>AG GFE | d>fg afa | geg fdA | G>AB cAF | G>AG GFE :| 
"^C" d2 e d3 | ded ^cBA | d2 e d2 A | GFG AFD | d2 e d3 | ded ^cBA | G>AB cAF | G>AG GFE :| 
"^D" def def | def e^cA | def def | G>AG GFE | def def | def e^cA | G>AB cAF | G>AG GFE :| 
"^E" D3 D3 | D3 ABc | D3 D3 | G>AG GFE | D3 D3 | D3 D3 | G>AB cAF | G>AG GFE :|"^F" [eA]3 [fB]3 | 
 BAG FED | [eA]3 [fB]3 | G>AG GFE | [eA]3 [fB]3 | BAG FED | G2 B cAF | G>AG GFE"_DS" :|  