need help with scaning 2D array

Graphics 640,480,32,1

SetBuffer BackBuffer()

Global CHECKS = 0
Dim ARRAY( 8 , 8 )
	
;populate
For l = 0 To 8
	Steps = 9 - l
	;top row
	For s = 0 To Steps - 1
		CHECK( l+s, s )
	Next
	;left column
	If l > 0
		For s = 0 To Steps - 1
			CHECK( s , l+s )
		Next
	EndIf
Next

;display
For y = 0 To 8
	For x = 0 To 8
		col = ( x  + y ) Mod 2
		If col = 0 
			Color 255,0,0
		Else
			Color 0,0,255
		EndIf
		Text x*30,y*30, ARRAY( x, y )
	Next
Next

Flip
WaitKey

;==================================
;==================================
;==================================

Function CHECK( x, y )

	ARRAY( x, y ) = CHECKS
	CHECKS = CHECKS + 1

End Function		

[EDIT] Similar to the above