repeat a matrix in defined manner

hi! How could i generate from this matrix:

 A=[1 2 3
    4 5 6  
    4 5 6]

this matrix:

 B= [1 1 1 1 2 2 2 2 3 3 3 3
     4 4 4 4 5 5 5 5  6 6 6 6 
     4 4 4 4 5 5 5 5  6 6 6 6]

thank you

Answer 1

[Azzi Abdelmalek]

A=[1 2 3;4 5 6;4 5 6];
m=4
B=cell2mat(arrayfun(@(x) x*ones(1,m),A,'un',0))

Answer 2

[Walter Roberson]

kron(A,[1 1 1 1])

or

A(:, repmat(1:end,4,1) )