It looks like you are trying to define an integration area in MATLAB using a Monte Carlo method. The image shows a checkerboard-like pattern within a square region. To define such a region in MATLAB, you need to apply a condition that alternates between included and excluded areas.
Here’s how you can define the checkerboard pattern in MATLAB:
% Define grid resolution
n = 100;
x = linspace(-1,1,n);
y = linspace(-1,1,n);
[X, Y] = meshgrid(x, y);
% Define checkerboard pattern (3x3 grid)
a = 2/3; % Size of each square in the 3x3 grid
res = mod(floor((X + 1) / a) + floor((Y + 1) / a), 2) == 1;
% Plot the region
figure;
imagesc(x, y, res);
colormap(gray);
axis equal;