Craft a musical piece that abides by the prescribed structural guidelines and the given theme.
X:1
L:1/8
M:6/8
K:Bmin
['FA |]:', 'BAF FEF DFA', 'b afb afe'  
X:1
L:1/8
M:6/8
K:Bmin
 FA |]: BcB BAF | FEF DFA | BcB BAF | d2 e fed | BcB BAF | FEF DFA | def geg | fdB B2 A :: 
 def a2 b | afb afe | dFA def | geg fdB | def a2 b | afb afe | def geg | fdB B2 A :|  