It is highly unlikely that Mary is in the hallway. It is probably the case that John moved to the office. It is impossible that Winona is a sheep. It is certain that if either 'Mary is in the hallway' or 'John moved to the office' but not both then Lily is white. There is a very good chance that if 'Mary is in the hallway' or 'Winona is a sheep' or both then Bernhard is a frog. It is impossible that if either 'Winona is a sheep' or 'John moved to the office' but not both then Brian is a swan.
It is impossible that 'Mary is in the hallway and Brian is a swan'.
It is impossible that 'Mary is in the hallway and Brian is a swan'.
It is probable that 'Mary is in the hallway and Brian is a swan'.

  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.
  0.0::factC.
  %hop1
  1.0::factX:-xor(factA,factB).
  0.8::factY:-or(factA,factC).
  0.0::factZ:-xor(factC,factB).

  %hop2
  conclusion:-and(factA,factZ).

  query(conclusion).
  
'Mary is in the hallway and Brian is a swan'.