Copyright (c) 2002 Karl Scherer

This game is played on an empty NxN square board (let's say 7x7)::

SETUP - Each player drops his stone on an empty cell.
TURNS - At each turn, each player must move his stone:
The stone moves similar to a chess Knight, but in two steps rather than one.
First it moves one (two) cell(s) in one direction, then two (one) cell(s) orthogonally (hence each player has two moves per turn).
All positions moved to or jumped over turn into an impenetrable barrier
for both players (i.e., they cannot be moved into or jumped over).
GOAL - The stalemated player loses.
An example

If Black moves to cell [1] then to cell [2], he will create three barriers at c6, c7 and d7 winning the game.

There is a ZRF to play Barrier with Zillions.