Craft a musical composition that adheres to the specified musical theme and letter-based structure.
X:1
L:1/8
M:2/2
K:C
['(3(EFG) cA', 'ecc a gede (TcBc)f (Tge)df eaaf (Tge)de']  
X:1
L:1/8
M:2/2
K:C
 G | (3(EFG) cA (TGFG)G | EGcG EDDG | (3(EFG) cA (TGFG).A | cded cAAG | (3(EFG) cA G3 G | 
 EGcG EDDG | (3(EFG) cA G3 a | gedf ecc || a | gede (TcBc)f | (Tge)df eaaf | (Tge)de (TcBc)A | 
 GcGF ECCf | (Tge)de TcBcf | gedf eaaf | geaf gedc | (3(ABc) GF Ec c2 |]  