# Vlak

import matplotlib.pyplot as plt
import numpy as np

plt.figure (figsize = (10, 10))

ax = plt.axes (projection = "3d")

a = -0.25
b = 15
grens = 10

x = np.arange (- grens, grens, 0.05)
y = np.arange (- grens, grens, 0.05)

x, y = np.meshgrid (x, y)

r = np.sqrt (x**2 + y**2)
z = a * np.exp (- (x**2 + y**2) / b)

ax.set_xlim ([- grens, grens])
ax.set_ylim ([- grens, grens])
ax.set_zlim ([-1, 3])

ax.plot_wireframe (x, y, z, color = "blue")

plt.axis ("off")
plt.show ()