So i've recently started to practise drawing (orientable) surfaces using TikZ wich resulted in my first figure that looks like this:
Which i am quite proud of, even though it might not be much. However, a few weeks ago i accidentally stumpled upon a few illustrations like this one in partcular
(source in picture description added)
and i would really love to know whether this was (possibly) done in TikZ or LaTeX in general and if you guys could give me a few hints on how to learn to create such figures by myself. I know that the TikZ-Manual is a good start but i feel a bit lost and even though i spent almost dozens of hours learning how to draw curved lines in TikZ i only managed to do my first figure mainly by accident to be honest.
To sum it up: Where would be a good start for me to learn how to draw such figures or what exactly would help me start learning this? For example: there are many different ways to draw curved lines. Which approach would help me the most if i wanted to recreate the 2nd figure basically? I am also quite curious on how to manage to do the vertical lines on the surface.
Any advise is highly appreciated.
Thank you very much!
PS: I am by no means looking for someone to recreate the shown figure. I am mainly interested in learning the skills to recreate such things by my own in the future.