import numpy as np
import mayavi.mlab as mlab


delta = 0.5


res = 200j

x, z = np.mgrid[-3:3:res,-3:3:res]
y = x**2 + delta

mlab.mesh(x, y, z)

if 1:
    y, x = np.mgrid[-3:3:res,-3:3:res]
    z = x**2 - delta

    mlab.mesh(x, y, z)

if 1:
    x, z = np.mgrid[-3:3:res,-3:3:res]
    y = z**2 + delta

    mlab.mesh(x, y, z)

mlab.orientation_axes()
mlab.show()