I remember one year at the Gathering for Gardner, the evening before the official start is a "Bar Bets and Cons" night. I was at a table and had gathered quite

I remember one year at the Gathering for Gardner, the evening before the official start is a "Bar Bets and Cons" night. I was at a table and had gathered quite a crowd, demonstrating various physics toys and math puzzles. I noticed someone standing a little way away, watching closely, nodding occasionally. He came up to me later in the evening and said "You've been doing a wonderful job! But now I have to re-write my talk ... you've shown half the toys I was going to talk about!". It was Tadashi. He is a lovely, lovely man. Some years later I was in the audience that was gathering for a talk he was about to give. He spotted me and came bounding up. "You may remember me ... we met at G4G." Humble, charming. And fiercely intelligent. EDIT: I wrote about the "Tinking Coffee Cup" way back in July 2015: * https://www.solipsys.co.uk/new/ChallengeQuestion.html#toc_name009 https://www.solipsys.co.uk/new/ChallengeQuestion.html#toc_na... I still use it.