Traditional 1D bar codes (with printed bars and spaces) are giving way to 2D bar codes that also include dots, hexagons, and even colors to encode more data. Bar-code scanners read 1D bar codes.

Mirko Baratta, Roberto Finesso, Daniela Misul, Ezio Spessa, Comparison between Internal and External EGR Performance on a Heavy Duty Diesel Engine by Means of a Refined 1D Fluid-Dynamic Engine Model, ...