Chances are slight that Brian is a rhino. It is highly unlikely that Lily is a lion. We believe that Greg is a frog. Chances are about even that if either 'Brian is a rhino' or 'Lily is a lion' but not both then Julius is green. There is little chance that if either 'Greg is a frog' or 'Lily is a lion' but not both then John moved to the office. We believe that if 'Lily is a lion and Greg is a frog' then Bernhard is yellow.
There is almost no chance that 'Bernhard is yellow and Greg is a frog'.
There is almost no chance that 'Bernhard is yellow and Greg is a frog'.
It is probably the case that 'Bernhard is yellow and Greg is a frog'.

  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
  0.1::factA.
  0.05::factB.
  0.75::factC.
  %hop1
  0.5::factX:-xor(factA,factB).
  0.1::factY:-xor(factC,factB).
  0.75::factZ:-and(factB,factC).

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

  query(conclusion).
  
'Bernhard is yellow and Greg is a frog'.