This is an absolutely wonderful WordPress site dedicated to showing visualizations of some wonderful geometric topology concepts / ideas / theories / constructs. It really is exquisite.
Mathematicians learning Lean by doing.
Doodles and Derivatives
Learning is never boring when the world is your classroom!
Some writings of a mathematical amateur
"A good stock of examples, as large as possible, is indispensable for a thorough understanding of any concept, and when I want to learn something new, I make it my first job to build one." - Paul Halmos
Come for the math, stay for the puns
Ruminations of a Graduate Class
Explorations in better, faster, stronger code.
Recent Progress and Open Problems
Topological Musings
A blog about probability and olympiads by Dominic Yeo
Physmatics in a nutshell, written and explained by a physmatician. Mobilis in mobili!
Where Algebra and Geometry Intersect
riemannian hunger 