In an unscheduled episode, Kris Boulton analyses a trainee teacher's volume-of-prisms sequence. He and Craig Barton work through key design principles — simplifying the rule, stripping out the arithmetic, starting with the general case, and building testing and expansion sequences that force genuine mathematical thinking. Access the show notes here: podcast.mrbartonmaths.com/227-breaking-down-an-example-sequence-with-kris-boulton