#內擺線（圓內螺線）
# python code is as follows:
import numpy as np
import matplotlib.pyplot as plt
t = np.linspace(0,2*np.pi,100)
plt.figure(figsize=(15,12),dpi=80)
for a in range(2,8):
x= np.cos(t)+np.cos(a*t)*1/a
y= np.sin(t)-np.sin(a*t)*1/a
plt.subplot(2,3,a-1)
plt.plot(x,y,color="blue",linewidth=5)
plt.show()
# The output is as follows:
