50	50	25		// nx ny nz
-245	-245	-45		// ox oy oz
 
10 10 10 10 10 10 10 10 10 10	// hx [0,1,... nz-1]
10 10 10 10 10 10 10 10 10 10	//     |
10 10 10 10 10 10 10 10 10 10	//     |
10 10 10 10 10 10 10 10 10 10	//     |
10 10 10 10 10 10 10 10 10 10	//     _

10 10 10 10 10 10 10 10 10 10	// hy
10 10 10 10 10 10 10 10 10 10
10 10 10 10 10 10 10 10 10 10
10 10 10 10 10 10 10 10 10 10
10 10 10 10 10 10 10 10 10 10

10 10 10 10 10 10 10 10 10 10	// hz
10 10 10 10 10 10 10 10 10 10
10 10 10 10 10 

// Grid is complete, data fields 
[cell data]
$sigma  // 3D array
$block
0   .005			// air-earth interface,  sigma half space conductivity 
nblocks=1
10  60 				// block dimensions in x
10  60				// y
100 140				// z
0.1 				// block conductivity
[cell data]

// need to be able to specify type of array scalar vector (# components), cell, edge face, name, type 
// how to do this general but not too bloated?

// Also, what if we want anisotropy, I guess just sigma_x etc.
// This file should ONLY contain data that pertains to the grid, so that the background reference 
// model probably doesn't fit?