// ------------------<<< Raster macro
#macro Raster(RScale, RLine)
pigment{
   gradient x scale RScale
   color_map{
     [0.000   color rgb<1,1,1>*0.5]
     [0+RLine color rgb<1,1,1>*0.5]
     [0+RLine color rgbt<1,1,1,1>]
     [1-RLine color rgbt<1,1,1,1>]
     [1-RLine color rgb<1,1,1>*0.5]
     [1.000   color rgb<1,1,1>*0.5]
            }
       } // end of pigment
#end// of "Raster(RScale, RLine)"

// -------------------<<<< Grid macro
#macro Grid(RasterScale,
            RasterHalfLine,
            Background_pigment)
plane{<0,1,0>, 0
       //layered textures!!!!
      texture{ Background_pigment
             } //  base color
      texture{ Raster(RasterScale,
                      RasterHalfLine)
             } // 2nd layer
      texture{ Raster(RasterScale,
                      RasterHalfLine)
               rotate<0,90,0>
             } // 3rd layer
     } // end of plane
#end // end of macro "Grid(...)"
// -----------------------------------
// use it:
object{Grid(0.50,0.035,
   pigment{color rgb<1,1,1>*1.1})}
// ------------------------- end -----