It is probably the case that Julius is gray. There is a better than even chance that Bernhard is a frog. Chances are slight that Mary got the apple. Chances are about even that if either 'Julius is gray' or 'Mary got the apple' but not both then Lily is a lion. It is almost certain that if either 'Mary got the apple' or 'Julius is gray' but not both then Gertrude is a cat. It is probable that if either 'Bernhard is a frog' or 'Julius is gray' but not both then Greg is yellow.
We doubt that 'Greg is yellow and Julius is gray'.
We doubt that 'Greg is yellow and Julius is gray'.
It is probably the case that 'Greg is yellow 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
  0.7::factA.
  0.6::factB.
  0.1::factC.
  %hop1
  0.5::factX:-xor(factA,factC).
  0.95::factY:-xor(factC,factA).
  0.7::factZ:-xor(factB,factA).

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

  query(conclusion).
  
'Greg is yellow and Julius is gray'.