Visualizing quaternions (4d numbers) with stereographic projection

If you enjoyed this, consider sharing it with some friends, and if you think the narrative structure here was really helpful to understand, maybe it will reassure those friends who would be put off by a big timestamp that good math really does pay off. . Many thanks to the sponsors among you. In fact, I've spent a lot more time than I'd like to admit on this project, so your patience and support is especially appreciated this time around.