show a digit matrix with segmentation line

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Answer 1

[Benjamin Großmann]

matrix = [ 1 1 1 1 2 2 2 2;
  1 1 1 2 2 2 2 2;
  3 3 3 3 3 2 2 2;
  3 3 3 3 3 3 3 3];

heatmap(matrix, 'Colormap', [1 0 0; 0 0 1; 0 1 0]) % <-- EDIT: colormap definition in heatmap function call changed
colorbar('off')

[HG]

I want to show a matrix like this photo with black line boundaries.

how can I do this ?

[Benjamin Großmann]

You can use patch() with properties 'FaceColor' and 'EdgeColor' to plot colored surfaces with black line boundaries.