It is highly unlikely that Brian is a rhino. Chances are slight that Jessica is a sheep. It is probable that John went to the garden. There is a very good chance that if either 'Brian is a rhino' or 'John went to the garden' but not both then Greg is white. It is highly unlikely that if 'John went to the garden' or 'Brian is a rhino' or both then Lily is a swan. We believe that if 'John went to the garden and Brian is a rhino' then Julius is a frog.
There is almost no chance that 'Brian is a rhino and Julius is a frog'.
There is almost no chance that 'Brian is a rhino and Julius is a frog'.
It is certain that 'Brian is a rhino and Julius 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
  0.05::factA.
  0.1::factB.
  0.7::factC.
  %hop1
  0.8::factX:-xor(factA,factC).
  0.05::factY:-or(factC,factA).
  0.75::factZ:-and(factC,factA).

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

  query(conclusion).
  
'Brian is a rhino and Julius is a frog'.