A physical object is provided that comprises a base medium, such as a paper sheet, and a memory tag embedded in it or attached to it. The memory tag stores at least one data item and location data relating each of one or more areas on the object's surface to a corresponding data item. Preferably, the data item or items stored by the tag comprise a print data item representing an item printed on the object, and/or a meta data item representing an instruction, or data to be output, in response to user selection of the corresponding area on the object's surface. Apparatus is provided for writing the data items and location data to the memory tag; apparatus is also provided for subsequently using the location data for interpreting user selections made by indicating positions on the object.