Matplotlib Animation : How to make a reverse animation?

Question

I'm currently working on matplotlib animation. Currently in the plot, I have 2 circles, green and orange one. What I want to make is shrinking the green circle until it came to zero (base of the cartesian diagram). What I got was a new blue circle coming out from the (0,0) coordinate. What I have to do if I want the green circle to shrink to (0,0) since the center of the green one is (0,0) also.

Thank you for the advice
Note : I'm using the 3.9.2 python with the latest update for all the packages

My current animation:

Current code :

import numpy as np
import matplotlib.pyplot as plt
import matplotlib.animation as animation


fig, ax = plt.subplots(1)
line, = ax.plot([], [], lw=2)
ax.set_xlim(-5,5)
ax.set_ylim(-5,5)

# Move left y-axis and bottim x-axis to centre, passing through (0,0)
ax.spines['left'].set_position('center')
ax.spines['bottom'].set_position('center')

# Eliminate upper and right axes
ax.spines['right'].set_color('none')
ax.spines['top'].set_color('none')

# Show ticks in the left and lower axes only
ax.xaxis.set_ticks_position('bottom')
ax.yaxis.set_ticks_position('left')

# theta goes from 0 to 2pi
theta = np.linspace(0, 2*np.pi, 100)
# the radius of the circle
r = np.sqrt(1)
r2 = np.sqrt(4)
# compute x1 and x2
x1 = 1+r*np.cos(theta)
y1 = r*np.sin(theta)

x2 = r2*np.cos(theta)
y2 = r2*np.sin(theta)
def init():
    line.set_data([], [])
    return line,
def animate(i):
    x2 = np.sqrt(i)*np.cos(theta)
    y2 = np.sqrt(i)*np.sin(theta)
    line.set_data(x2, y2)
    return line,
# create the figure
ax.plot(x1,y1)
ax.plot(x2,y2)
ax.set_aspect(1)
plt.grid()
anim = animation.FuncAnimation(fig, animate, init_func=init,
                                frames=200, interval=10)

plt.show()

f = r"D:/UNPAR/Semester 2/Pemrograman Komputer/Project/animation.gif" 
writergif = animation.PillowWriter(fps=30) 
anim.save(f, writer=writergif)