It is probably not the case that John went to the hallway. It is unlikely that Lily is a swan. There is little chance that Bernhard is a lion. We believe that if either 'John went to the hallway' or 'Lily is a swan' but not both then Julius is gray. There is little chance that if 'Bernhard is a lion' or 'John went to the hallway' or both then Brian is a rhino. There is a better than even chance that if 'Bernhard is a lion and Lily is a swan' then Greg is a swan.
Chances are about even that 'Bernhard is a lion and Julius is gray'.
There is almost no chance that 'Bernhard is a lion and Julius is gray'.
Chances are about even that 'Bernhard is a lion and Julius is gray'.

  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
  0.25::factA.
  0.2::factB.
  0.1::factC.
  %hop1
  0.75::factX:-xor(factA,factB).
  0.1::factY:-or(factC,factA).
  0.6::factZ:-and(factC,factB).

  %hop2
  conclusion:-and(factC,factX).

  query(conclusion).
  
'Bernhard is a lion and Julius is gray'.