function [x, y] = RandomWalk2D(N)
% Simulate a 2D random walk in a 2N-1 by 2N-1 grid.
% N is a positive integer.
% Walk starts from (0,0) and continues until the an edge, abs(N),
% is reached.
% x and y are row vectors with the property that (x(k),y(k)) is the
% location of the token after k hops, k=1:length(x).
% Initializations...
k=0; xc=0; yc=0;
% In general, (xc,yc) is the location after k hops.
while abs(xc)