Selecting randomly from matrix

I have a matrix B =

     2     5     6
     8     9    10
    56    89    10
     1     0     3
     8     1     3

in this i want to select a 2x2 matrix randomly ,please tell how to select

[Walter Roberson]

A 2x2 submatrix of adjacent values?

[FIR]

Yes walter

Answer 1

[Andrei Bobrov]

adjacent values

B(randi(size(B,1)-1)+(0:1),randi(size(B,2)-1)+(0:1));

not adjacent values

ii = randperm(size(B,1));
jj = randperm(size(B,2));
B(sort(ii(1:2)),sort(jj(1:2)))

Answer 2

[Thomas]

perhaps something like this..

q=[  2     5     6
8     9    10
56    89    10
1     0     3
8     1     3]

row=randi(4);   %select start row
col=randi(2);   %select start colums
out=q(row:row+1,col:col+1)