Some years ago (oh dear - 39!) I used to have a boss who was elderly ie early 60s, same age as I am now
Ted had perfected the game of sleeping on the job. He would have a page in front of him and be writing with his head bent down over the page. It was all paper 'n pen in those days of course. However, he could stop writing, nod off for even an hour or more, but leave the pen in place in his hand and poised on the page half way through a word. He must have practiced that for years. If anyone came to his office he would simply write a line or two before looking up. What he wrote was usually total gibberish - but the caller never new that.
Ted was a super boss, just like a dad to some of us juniors. Within our group he fully admitted his "nod-off" technique.
The system did fail a few times. I well remember one day when the "super-boss" called but opened Ted's office door quite quietly. Ted never moved. Obviously too far gone that day. The big boss bent down, looked at Ted's sleeping face - and crept out closing the door quietly. With a big smile he told us not to tell Ted that he had called. Those were the days. Happy days when everyone in the workplace was civilised.