surfc
Surface plot of a function of two variable with a contour plot of the surface.
`surfc(z)`
`surfc(x,y,z)`
 Inputs `z` An `mXn` matrix of the function values to plot. `x` Either a vector of length `n` or a matrix of size `mXn` . `y` Either a vector of length `m` or a matrix of size `mXn` .

Description
The inputs `x` and `y` should either be both vectors, or matrices of the indicated size. In the former case, the function is assumed to be of the form `z[i,j]=f(x[j], y[i])` . Otherwise, the functional form `z[i,j]=f(x[i,j],y[i,j])` is assumed.

Each region defined by `x[i,j]<=x<=x[i,j+1], y[i,j]<=y<=y[i+1,j]` is filled with the same color, which is determined by the average `z` value in this region. Further, the boundaries of of each of these regions are drawn in black.

The contour plot of the function (lines along which the interpolated value of `z` is constant) is also drawn in the `x-y` plane.
Example
```>>x=[0:.02:1]'
>>y=x
>>z=sin(x*pi)*cos(2*x'*pi)
>>surfc(x,y,z)
>>title('Surface Plot with Contour')
``` 