a = 1;
figure('Position',[0 0 800 800])
for i = 1 :5
   [n m] = size(a);
    Z = zeros(n,m);
    a = [a,Z,a;
         a,a,a;
         a,Z,a
         ];
end
imagesc(a);
colormap bone;axis off;
caxis([0, 1]);

clc; clear all;
a = 1;
figure('Position',[0 0 800 800])
for i = 1 :5
   [n m] = size(a);
    Z= zeros(n,m);
    a = [Z,a,Z;
         a,a,a;
         Z,a,Z
         ];
end
imagesc(a);
colormap bone;axis off;
caxis([0, 1]);

clc; clear all;
a = 1;
figure('Position',[0 0 800 800])
for i = 1 :5
   [n m] = size(a);
    Z= zeros(n,m);
    a = [a,a,a;
         a,Z,a;
         a,a,a
         ];
end
imagesc(a);
colormap bone;axis off;
caxis([0, 1]);

clc; clear all;
a = 1;
figure('Position',[0 0 800 800])
for i = 1 :5
   [n m] = size(a);
    Z= zeros(n,m);
    a = [a,Z,a;
         Z,a,Z;
         a,Z,a
         ];
end
imagesc(a);
colormap bone;axis off;
caxis([0, 1]);

clc; clear all;
a = 1;
figure('Position',[0 0 800 800])
for i = 1 :5
   [n m] = size(a);
    Z= zeros(n,m);
    if mod(i,2) == 0
    a = [Z,a,a;
         a,a,a;
         a,a,a
         ];
    else
          a = [a,a,a;
               a,Z,a;
               a,a,a
             ];
    end
end
imagesc(a);
colormap bone;axis off;
caxis([0, 1]);