Develop a musical piece using the given theme and incorporating the letter-based structure provided.
X:1
L:1/8
Q:1/8=180
M:4/4
K:Emin
['EFGB BAdB A2 FB AGFD EFGB BABg', 'gebe gebe']  
X:1
L:1/8
Q:1/8=180
M:4/4
K:Emin
 F | EFGB BAdB | A2 FB AGFD | EFGB BABg | fedf edBA | EFGB BAdB | A2 FB AGFD | EFGB BABg | 
 fedf e3 :| f | gebe gebe | fdad fdaf | gebe gebe | fedf e2 ef | gebe gebe | fdad fdaf | 
 gbag fgaf | gfe^d e3 :|  