There was a bank row!

Last weekend I gave our readers a puzzle which, I said, only a segment of our readers could possibly solve. But even amongst them there were very few who succeeded. One exception: super-talent Gukesh, who managed – with a little help. And he collapsed in helpless laughter when he got it. Another super-talent, Leon Mendonca, filmed it all. Here is the solution, together with a second prank I played on a young chess talent.