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

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

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]>>>.