The Professor was in his study working on some project or another.  He looked up from his work, he decided that the time was right.  He stood up and moved to his office.  He wrote a note, put it in a tube.  The tube he, after a moment's thought, placed into one of several pipes where it was whisked off to where Simon was at the moment.  No matter where he was or what he was doing, the Professor always seemed to be able to find him.<br/>The note itself said "Simon, please meet me in my office, I have work for you." and it was signed with a stylised 'P'.  And then he waited.