A barcode is an optical machine-readable representation of data, which shows data about the object to which it attaches. Originally barcodes represented data by varying the widths and spacings of parallel lines, and may be referred to as linear or 1 dimensional (1D). Later they evolved into rectangle

Rectangle

In Euclidean plane geometry, a rectangle is any quadrilateral with four right angles. The term "oblong" is occasionally used to refer to a non-square rectangle...

s, dot

Dot

- Typography :* Full stop, also called period in American English, used as a sentence terminator and as a decimal separator in numerals - Typography :* Full stop, also called period in American English, used as a sentence terminator and as a decimal separator (decimal point) in numerals -...

s, hexagons and other geometric patterns in 2 dimensions (2D).