How can I plot a few dots in matrix plot?

for example, I want to plot this one:

Answer 1

[KSSV]

[X,Y] = meshgrid(1:5,1:5) ;
plot(X,Y,'*')

A = ones(5) ;
spy(A)

Answer 2

[Walter Roberson]

[X,Y] = meshgrid(6:6:24);
scatter(X, Y, 'b*')
xlim([0 30]); ylim([0 30])

[Dan Kanyas]

amazing!