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
