1:- table d/1,e/1.
2
3top :- abolish_all_tables, d(_), fail.
4top.
5
6% Two mutually recursive predicates:
7d(X) :- e(Y), Y < 20000, X is Y + 1.
8d(0).
9
10e(X) :- d(Y), Y < 20000, X is Y + 1.
11e(0).
12