Yes that was a fun lesson and certainly got the grey matter going. I have learned a great deal from it and no longer fear Binary. The whole course has been fun and very educational. I particularly like the way the lessons are put together, mainly textbooks and the Internet were of little or no use at all when answering the questions, and I really had to think quite hard most of the time.
Thank you for a fun year or so and for marking my work. I have found your comments encouraging and helpful. I enclose a cheque to begin The Nature of the Stars.