Given a character matrix, your task is to identify the positions of all squares with a length of at least 3 and output the row and column numbers of the bottom-right corner of these squares. The squares are composed of the same character, and each side has a length of at least 3.

If the matrix is

T N G F I M O
I U G I C S V
I N U Z R Y C
V V Y A G O R
Y N Z Y D M V
P W S X C E K
Q B W P O A D
N Z C P T C N
J A M Z H E J
S Q O Z B P B
X X X U C C O
X X X O J U R
X X X O L R H

Please provide the row and column of the bottom-right vertex of the square in the character matrix with a side length of at least 3 (the answer is unique). Notice: All coordinates start from 0.  

Your answer should be in the format <<<[row, column]>>>.