import numpy as np 
import matplotlib.pyplot as plt 
from matplotlib import animation 
 
# New figure with white background 
fig = plt.figure(figsize=(6,6), facecolor='white') 
 
# New axis over the whole figure, no frame and a 1:1 aspect ratio 
ax = fig.add_axes([0, 0, 1, 1], frameon=False, aspect=1) 
 
# Number of ring 
n = 50 
size_min = 50 
size_max = 50 ** 2 
 
# Ring position 
pos = np.random.uniform(0, 1, (n,2)) 
 
# Ring colors 
color = np.ones((n,4)) * (0,0,0,1) 
# Alpha color channel geos from 0(transparent) to 1(opaque) 
color[:,3] = np.linspace(0, 1, n) 
 
# Ring sizes 
size = np.linspace(size_min, size_max, n) 
 
# Scatter plot 
scat = ax.scatter(pos[:,0], pos[:,1], s=size, lw=0.5, edgecolors=color, facecolors='None') 
 
# Ensure limits are [0,1] and remove ticks 
ax.set_xlim(0, 1), ax.set_xticks([]) 
ax.set_ylim(0, 1), ax.set_yticks([]) 
 
def update(frame): 
  global pos, color, size 
 
  # Every ring is made more transparnt 
  color[:, 3] = np.maximum(0, color[:,3]-1.0/n) 
 
  # Each ring is made larger 
  size += (size_max - size_min) / n 
 
  # Reset specific ring 
  i = frame % 50 
  pos[i] = np.random.uniform(0, 1, 2) 
  size[i] = size_min 
  color[i, 3] = 1 
 
  # Update scatter object 
  scat.set_edgecolors(color) 
  scat.set_sizes(size) 
  scat.set_offsets(pos) 
 
  # Return the modified object 
  return scat, 
 
anim = animation.FuncAnimation(fig, update, interval=10, blit=True, frames=200) 
plt.show()