It wasn’t all lecture halls, discussion rooms, and cafeterias for the workshop. The organizers arranged for a boat tour last week, and we all sat on one of those splendid long, wide and low tour boats that you often see on the canals in Amsterdam. It was nicely equipped with a bottle of wine at each table, and the crew members handed us each a glass of sparkling wine as we embarked. Very nice. There was a lot of fun chatter from each table for the whole trip around the canals (so much so that they stopped the attempts to inform us over the PA system about some of the sights we were seeing, since the sound was drowned out by the conversations), covering (from what I could hear) a wide range of topics from well beyond physics to matters concerning topics presented in the workshop.
Sometimes pads of paper and pens appeared. Above is a group (David Tong, Liza Huijse, Mark Van Raamsdonk and Atish Dabholkar) engaged in a discussion about (if I recall correctly) an amusing mathematical puzzle (David presented it) that had a remarkably striking answer. (Actually, you can see our mutual friend Ed Copeland explain it all here on YouTube.)