For? 0 we naturally get a circle; for? 0 we obtain two tangentcircles.
对? 0我们当然得到一个圆;对? 0得到两个相切的圆。
2
The green spiral is made from quarter-circlestangent to the interior of each square, while the red spiral is a Golden spiral, a special type of logarithmic spiral.
That is a vector field in which the trajectories are going to be circles centered in the z-axis and our vector field is just going to be tangent to each of these circles.