[python] 4.比心

效果：

实现：

import numpy as np
import matplotlib.pyplot as bear
x = y = np.arange(-4, 4, 0.01)
x, y = np.meshgrid(x,y)
bear.contour(x, y, (x**2 + y**2-8.88)**3-x**2*y**3,[0])
bear.axis('scaled')
bear.show()