Global metadata, such as a document identifier, which may be a globally
unique identifier, is embedded into an embedded interactive code document
by combining a first m-array and a plurality of copies of the first
m-array to generate a combined m-array with encoded global metadata such
that respective start positions (x.sub.d,y.sub.d).sup.i of the plurality
of copies of the first m-array in the combined m-array are each shifted,
by respective amounts that are based on respective portions of the global
metadata, relative to a start position of the first m-array in the
combined m-array. Global metadata may be decoded from the combined
m-array by determining the respective amounts by which the plurality of
copies of the first m-array are shifted, relative to the first m-array,
in the combined m-array and by combining the respective amounts to
produce a decoded value of the global metadata.