US Patent 7941010 System for generating interface surface

A system for generating an interface surface is provided having a code generator for generating machine-readable coded data and a printer for printing the generated coded data onto a surface to generate an interface surface. The coded data is generated to be arranged in accordance with a layout having n-fold rotational symmetry about a center of rotation, where n is at least two, the layout including n identical sub-layouts rotated 1/n revolutions apart about the center of rotation. Each sub-layout defines the position of data elements and includes rotation-indicating data that distinguishes that sub-layout from at least one other sub-layout.