Machine-readable coded data disposed on or in a substrate. The coded data includes a plurality of layouts located in a region, each layout having n identical sub-layouts rotated 1/n revolutions apart about a center of rotation. Each layout encoding a first codeword formed from a sequence of n first symbols, with each sub-layout defining the position of a respective one of the first symbols such that the first codeword is indicative of the orientation of the layout. Each layout also partially encodes a third codeword at least partially indicative of an identity of the region such that the region identity may be determined from two or more of the layouts.
CROSS REFERENCE TO RELATED APPLICATION
The present application is a continuation of U.S. application Ser. No. 10/409,864 filed Apr. 9, 2003, the entire contents of which are herein incorporated by reference.
A product 2 has a data encoding pattern 6 thereon. The pattern comprising a plurality of pattern cells 200 each of which has a pattern selected from a group of cell patterns. Each cell pattern comprises a plurality of cell elements 204 each of which can have any of a plurality of marking states, such that the marking states of the elements produce the cell pattern. Each cell pattern has at least two lines of symmetry. At least some of the cells are arranged in a manner which is dependent on the position of the content
