Develop a musical piece using the given theme and incorporating the letter-based structure provided.
X:1
L:1/8
M:4/4
K:A
['A2 AA A2 CD (FE)EE E2', 'A2 ue2 (ce)ee (ef)ed cBcd efec (df)ff']  
X:1
L:1/8
M:4/4
K:A
 vcB | A2 AA A2 CD | (FE)EE E2 AB | c2 cc (dc)BA | (cB)BA (Bd)cB | A2 AA A2 CD | (FE)EE E2 ed | 
 ceee ecAB | (cA)AA A2 :| ue2 | (ce)ee (ef)ed | cBcd efec | (df)ff (fg)fe | dcde fgfe | ceag fedc | 
 dcBA B2 (ce) | ecaf ecAB | (cA)AA A2 |]  