These arrays are used to get row and column numbers of 8 neighboursof a given cell
static int [ ] rowNum = { - 1 , - 1 , - 1 , 0 , 0 , 1 , 1 , 1 } ; static int [ ] colNum = { - 1 , 0 , 1 , - 1 , 1 , - 1 , 0 , 1 } ;