Similarly, the '-i', '-j', and '-k' values, if not otherwise used,     
 will be loaded with the voxel spatial index coordinates.  The '-l'     
 (letter 'ell') value will be loaded with the temporal index coordinate.

 The '-n' value, if not otherwise used, will be loaded with the overall 
 voxel 1D index.  For a 3D dataset, n = i + j*NX + k*NX*NY, where       
 NX, NY, NZ are the array dimensions of the 3D grid.  [29 Jul 2010]     

 Otherwise undefined letters will be set to zero.  In the future, new   
 default values for other letters may be added.                         

 NOTE WELL: By default, the coordinate order of (x,y,z) is the order in 
 *********  which the data array is stored on disk; this order is output
            by 3dinfo.  The options below control can change this order:

 -dicom }= Sets the coordinates to appear in DICOM standard (RAI) order,
 -RAI   }= (the AFNI standard), so that -x=Right, -y=Anterior , -z=Inferior,
                                        +x=Left , +y=Posterior, +z=Superior.

 -SPM   }= Sets the coordinates to appear in SPM (LPI) order,           
 -LPI   }=                      so that -x=Left , -y=Posterior, -z=Inferior,
                                        +x=Right, +y=Anterior , +z=Superior.