The 5 and 7 in row 13 are only separated by the column with the zero, forming the tips of two pointy noses. continue the noses to upward diagonals moving outward for 3 more pixels, the outer 3 columns on each end are empty in the bottom row, then the 4 and the 6 begin, from those outer ends of the 4 and 6, move upward and outward to the border. logical from there.