It is highly unlikely that Mary left the football. It is likely that Julius is green. It is highly unlikely that Winona is a wolf. It is highly unlikely that if either 'Winona is a wolf' or 'Mary left the football' but not both then Emily is a mouse. There is little chance that if 'Julius is green' or 'Mary left the football' or both then Bill went to the garden. It is unlikely that if either 'Winona is a wolf' or 'Julius is green' but not both then Greg is white.
It is impossible that either 'Julius is green' or 'Winona is a wolf' but not both.
It is likely that either 'Julius is green' or 'Winona is a wolf' but not both.
It is impossible that either 'Julius is green' or 'Winona is a wolf' but not both.

  and(A,B) :- A,B.
  or(A,B) :- A;B.
  nand(A,B) :- not(and(A,B)).
  nor(A,B) :- not(or(A,B)).
  xor(A,B) :- or(A,B), nand(A,B).

  %hop0
  0.05::factA.
  0.7::factB.
  0.05::factC.
  %hop1
  0.05::factX:-xor(factC,factA).
  0.1::factY:-or(factB,factA).
  0.2::factZ:-xor(factC,factB).

  %hop2
  conclusion:-xor(factB,factC).

  query(conclusion).
  
Either 'Julius is green' or 'Winona is a wolf' but not both.