B	B	B	B	B	B	B	B	B	B
	A		B	B	B	B	B	B	B	B	B
	A	A		B	B	B	B	B	B	B	B
	A	A	A		B	B	B	B	B	B	B
	A	A	A	A		B	B	B	B	B	B
	A	A	A	A	A		B	B	B	B	B
	A	A	A	A	A	A		B	B	B	B
	A	A	A		A	A	A		B	B	B
	A	A	A		A	A	A	A		B	B
	A	A	A	A	A	A	A	A	A		B
	A	A	A	A	A	A	A	A	A	A