Coded data for disposal on or in a surface, the coded data being arranged
in accordance with at least one layout having n-fold rotational symmetry
about a center of rotation, where n is at least two, and having mirror
symmetry, the layout including: (a) n identical first sub-layouts
rotated 1/n revolutions apart about the center of rotation, and, (b) n
identical second sub-layouts rotated 1/n revolutions apart about the
center of rotation, each second sub-layout being a reflection of a
corresponding one of the first sub-layouts, at least one sub-layout
including: (i) rotation-indicating data that distinguishes that
sub-layout from at least one other sub-layout; and, (ii)
reflection-indicating data that distinguishes the reflection of that
sub-layout from the reflection of a corresponding reflected sub-layout.