The student becomes the teacher

I have recently been visiting with my friend's elderly neighbor.  He is quite a kick.  So I decided to teach him how to do Sudoku. Since he had never done it, much less heard of it, I started out with a simpler version.  To my surprise and delight (his, too) he loves it and caught on right away.  He isn't quite ready for the full version, so I have made up blanks and filled in some of the numbers, myself.  Yesterday he flew through the six puzzles I made for him in a record amount of time.  I even made a couple of puzzles with symbols instead of numbers.  Today I find myself rattling my brain to come up with new ones that will take him more than a minute a piece to do.  My point is that many times, the student becomes the teacher.  By the way, he corrected me about his age, he is only 93! Make a ripple, be willing to learn, see what happens.