Test of fibonacci numbers

fibonacci(0,1).
fibonacci(1,1).
diff(0,1).
diff(1,2).
diff(2,3).
diff(3,4).
diff(4,5).
diff(5,6).
diff(6,7).
diff(7,8).
diff(8,9).
sum(1,1,2).
sum(1,2,3).
sum(2,3,5).
sum(3,5,8).
sum(5,8,13).

fibonacci(N2,Q),fibonacci(N1,P),diff(N1,N),diff(N2,N1),sum(Q,P,R) :> fibonacci(N,R).

Query: fibonacci(8,X).