blender spiral cup

add mesh-> circle

select alternative vertices on circle, s to scale

e to extend

ctrl+r to loop cut

turn on proportion editing, select middle loop, scale down

select bottom circle, f to add face, r to rotate

select top circle, r to rotate

reference:

https://buildbee.com/blog/article/tutorial-how-to-use-blender#:~:text=Create%20a%20circle%3A%20Click%20Layout,the%20%E2%80%9CAdd%20Circle%E2%80%9D%20dialog.