In a two-dimensional code, a plurality of unit cells are arranged in two-dimension.
Each of the unit cells indicates one of at least three colors, such as, "white",
"black", "red", "blue", and "green". Each color of each of the unit cells is optically
readable and represents a data value set to each of the unit cells. In the two-dimensional
code, a specifying pattern portion is provided. The specifying pattern portion
includes a plurality of color reference cells and is configured to specify positions
of the unit cells. The color reference cells indicates all of the at least three colors.