# Diabolo

import matplotlib.pyplot as plt
import numpy as np

from matplotlib import cm, colors
from mpl_toolkits.mplot3d import Axes3D

phi, z = np.mgrid [0:2 * np.pi:720j, -1:1:200j]

r = np.abs (z)
x = r * np.cos (phi)
y = r * np.sin (phi)

fig = plt.figure (figsize = (8, 8))

ax = fig.add_subplot (111, projection = "3d")

ax.plot_surface (x, y, z, alpha = 0.2, linewidth = 0.1)

ax.set_xlim ([-1.1, 1.1])
ax.set_ylim ([-1.1, 1.1])
ax.set_zlim ([-1.1, 1.1])

ax.set_aspect ("equal")
ax.plot_wireframe (x, y, z, color = "orange")

plt.show ()