Occasionally an A-to-Z gives me the chance to naturally revisit an earlier piece. Orthonormal, from the Leap Day 2016 series, was one of those. It builds heavily on orthogonal, discussed the year before. When you know what the terms mean, of course it would. But getting to what the terms mean is part of the point of these essays.
Also, I hope to publish the 141th installment of the Playful Math Education Blog Carnival this weekend. If you’ve found a mathematics page, video, game, anything that delights or teaches or both, please mention in the comments. I’m eager to share it with more people.