I really think that this is a jaw dropping bit of Mathematics and it really is frightening to see how intelligent people are fooled by it. It"s a powerful lesson and a great bit of Maths and ToK where the Maths is directly relevant to the syllabus. Don"t miss the opportunity to teach a lesson on this! If you are not familiar with it - and I wasn"t until someone told me about it - then spend a bit of time with it and...