There is an intriguing structure on display in downtown Seattle’s Westlake Center. I walk by there on the way to my firm’s downtown office sometimes, and I finally took a picture. So what is it? Well, it’s a polychoron, but a very complicated one with 1-4-8-4-1 outside vertices (with the bottom vertex cut off to make it stand on its own!). Polychora are closed four-dimensional figures, with cells inside. A tesseract has 8 cells, but the one at Westlake Center has too mind-bogglingly many too count.