Link 3D animation examples to one another.

Also use double quotes in English text.
Also inline definition of Z array; it's not as the docstring of
generate() was helpful at all.

examples/mplot3d/rotate_axes3d_sgskip.py

@@ -5,7 +5,7 @@
 
 A very simple animation of a rotating 3D plot about all 3 axes.
 
-See wire3d_animation_demo for another simple example of animating a 3D plot.
+See :doc:`wire3d_animation_sgskip` for another example of animating a 3D plot.
 
 (This example is skipped when building the documentation gallery because it
 intentionally takes a long time to run)

examples/mplot3d/wire3d_animation_sgskip.py

@@ -3,7 +3,7 @@
 Animating a 3D wireframe plot
 =============================
 
-A very simple 'animation' of a 3D plot.  See also rotate_axes3d_demo.
+A very simple "animation" of a 3D plot.  See also :doc:`rotate_axes3d_sgskip`.
 
 (This example is skipped when building the documentation gallery because it
 intentionally takes a long time to run)
@@ -14,14 +14,6 @@
 import time
 
 
-def generate(X, Y, phi):
-    """
-    Generates Z data for the points in the X, Y meshgrid and parameter phi.
-    """
-    R = 1 - np.sqrt(X**2 + Y**2)
-    return np.cos(2 * np.pi * X + phi) * R
-
-
 fig = plt.figure()
 ax = fig.add_subplot(projection='3d')
 
@@ -40,9 +32,9 @@ def generate(X, Y, phi):
     # If a line collection is already remove it before drawing.
     if wframe:
         wframe.remove()
-
+    # Generate data.
+    Z = np.cos(2 * np.pi * X + phi) * (1 - np.hypot(X, Y))
     # Plot the new wireframe and pause briefly before continuing.
-    Z = generate(X, Y, phi)
     wframe = ax.plot_wireframe(X, Y, Z, rstride=2, cstride=2)
     plt.pause(.001)