# How to color a 3d plot by z-level?

I'd like to color a 3d plot based on z-level. I think this is easy to do in Maple or Mathematica, but I've been searching the web for help on doing this in Sage and can't find anything to help with plot3d or implicit_plot3d.

Here's the implicit_plot3d I'm using.

```
var('x,y,z')
implicit_plot3d(x^2-y^2*z == 0,(x,-4,4),(y,-4,4),(z,-4,4)).show(mesh=True)
```

Also, are there color maps in Sage that produce plots with colors and lighting similar to the default in Mathematica?

Niles also eventually opened up the possibly relevant http://trac.sagemath.org/sage_trac/ticket/12212