I did mean to include a mention of this in yesterday’s post, but I misplaced the link and feel a bit silly about that now. Anyway, over the course of the Summer 2015 and the Leap Day 2016 A To Z I’ve had the chance to talk about a bunch of concepts including duals and Riemann spheres and nontrivial subsets of things. Baking And Math, which combines discussions of mathematics with cooking tips, is as far as I know unaware of my existence. But the blog’s made use of these kinds of things in describing the Poincaré homology sphere. I’m not sure that I can explain why this is an interesting shape to study, especially not this weekend as I’ve been busy with some pinball events. But the shape looks great, and the essay describes some of the making of this wonderful shape. You can appreciate it for beauty bare.