Machine-readable coded data disposed on or in a substrate in accordance
with a layout, and method of generating such coded data, The layout has
six-fold rotational symmetry and includes 6 identical sub-layouts rotated
1/6 revolutions apart about a center of rotational symmetry of the
layout. The coded data is disposed in accordance with each sub-layout
including rotation-indicating data that distinguishes the rotation of
that sub-layout from the rotation of at least one other sub-layout within
the layout. In one embodiment, the symbols of the sub-layouts are
interleaved with each other