Develop a musical piece using the given theme and incorporating the letter-based structure provided.
X:1
L:1/8
Q:1/8=80
M:4/4
K:none
['gA{g}dfge{g}fd |{g} ec{gcecG} c2{g} ef{a}ge a{g}a{g}agag{a}ed', 'cBAB{g}c{d}A{g}Bd e{g}e{A}ed{g}cd{g}ec |{gdedG} d2{g} dc{g}df{g}ed c2{e} A2{GAG}']  
X:1
L:1/8
Q:1/8=80
M:4/4
K:none
 ag |{a} gA{g}dfge{g}fd |{g} ec{gcecG} c2{g} ef{a}ge | a{g}a{g}agag{a}ed | 
{gcd} c2{e} A2{GAG} A2 ag ||{a} gA{g}dfge{g}fd |{g} ec{gcecG} c2{g} ef{a}ge | a{g}a{g}agag{a}ed | 
{g} ce{g}dcB{G} A3 B ||{gcd} cBAB{g}c{d}A{g}Bd | e{g}e{A}ed{g}cd{g}ec |{gdedG} d2{g} dc{g}df{g}ed | 
{gcd} c2{e} A2{GAG} A2 B2 |]  