hidden1 :- 1 x, -1 y, 0.5. [activation=signum]
hidden2 :- 1 x, -1 y, -0.5. [activation=signum]

-1 xor :- hidden1. [activation=identity]
1 xor :- hidden2. [activation=identity]

xor/0 [offset=1.0, activation=identity]
