4. The system of claim 1 , wherein said pen comprises a memory buffer for storing said indicating data.
1. A system for printing and interacting with a document, said system comprising: (A) a computer system configured for: receiving a request for printing said document, said document containing visible information; allocating a document identity to said document; determining coded data for said document, said coded data encoding a plurality of locations on said document and identifying said document identity; and sending print data to a printer; (B) a printer connected to said computer system, said printer being configured for: receiving the print data; and printing the document so that the printed document includes said visible information superimposed with said coded data, said printer being configured to print the visible information and the coded data at the same time; and (C) an optically imaging pen configured for: interacting with the printed document; imaging at least some of the printed coded data; generating indicating data using the sensed coded data, said indicating data identifying the document identity and a position of the pen relative to the printed document; and sending the indicating to the computer system, wherein said computer system is further configured for interpreting the indicating data using a stored page description retrievable using said document identity contained in said indicating data.