On some food products there is a graphic, 2.5 cm x 2.5 cm consisting of 3 squares in upper left, upper right and lower left, and the rest of the graphic is filled in with black or white pixels. It looks like some sort of computer readable code, does anyone know what it it’s for ? It’s separate from the barcode. I’m looking at a can of Australian Tomatos, and it’s printed on the bottom of the can.