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

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

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]>>>.