Embedding 2D figures in a 3D figure

We have seen in Chapter 3, Working with Annotations, how to annotate figures. A powerful way to annotate a three-dimensional figure is to simply use two-dimensional figures. This recipe is a simple example to illustrate this possibility.

How to do it...

To illustrate the idea, we are going to plot a simple 3D surface and two curves using only the primitives that we have already seen before, as shown in the following code:

import numpy as np
from mpl_toolkits.mplot3d import Axes3D
import matplotlib.pyplot as plt
x = np.linspace(-3, 3, 256)
y = np.linspace(-3, 3, 256)
X, Y = np.meshgrid(x, y)
Z = np.exp(-(X ** 2 + Y ** 2))
u = np.exp(-(x ** 2))

fig = plt.figure()
ax = fig.gca(projection = '3d')
ax.set_zlim3d(0, 3)
ax.plot(x, u, zs=3, zdir='y', lw = 2, color = '.75')
ax.plot(x, u, zs=-3, zdir='x', lw = 2., color = 'k')
ax.plot_surface(X, Y, Z, color = 'w')

plt.show()

The preceding code will produce the following figure:

The black and gray curves are drawn as...