What are good and user-friendly math-softwares for 3d-visualization as in
https://www.youtube.com/watch?v=x7d13SgqUXg (sphere-eversion process).
https://www.youtube.com/watch?v=rB83DpBJQsE (divergence curl)
https://www.youtube.com/watch?v=r18Gi8lSkfM (Fourier Transform)