// Sample scene. 'yuqk matrix.pov +w800 +h800 +p +mv3.8'
    global_settings { assumed_gamma 1.0 }
    #declare VarOrthoMult =
        3.0/max(image_width/image_height,image_height/image_width);
    #declare Camera01z = camera {
        orthographic
        location <0,0,-2>
        direction z
        right VarOrthoMult*x*max(1,image_width/image_height)
        up VarOrthoMult*y*max(1,image_height/image_width)
    }
    #declare FnMx = function {
        transform {
#if (0)
            matrix <
                1.0, 1.0, 0.0,  // Shear in y by x 'transform'
                0.0, 1.0, 0.0,
                0.0, 0.0, 1.0,
                0.0, 0.0, 0.0>
            matrix <
                1.0, 0.0, 0.0,  // Shear in x by y 'transform'
                0.9, 1.0, 0.0,
                0.0, 0.0, 1.0,
                0.0, 0.0, 0.0>
#else
            matrix <      // Singular matrix error if 1x1 shear
                1.0, 1.0, 0.0,   // Shear in y 'transform'
                0.9, 1.0, 0.0,
                0.0, 0.0, 1.0,
                0.0, 0.0, 0.0>
#end

            inverse       // Match pure checker pattern form below
        }
    }
    // checker block pattern returns 0 or 1 (raw_wave not needed)
    #declare FnChkr = function { pattern {checker} }
    plane { -z 0
        pigment {
#if (0)
            function { FnChkr(FnMx(x,y,z).x,
                              FnMx(x,y,z).y,
                              FnMx(x,y,z).z) }
            scale 1/6
#else
            checker
#if (0)
            matrix <
                1.0, 1.0, 0.0,  // Shear in y by x
                0.0, 1.0, 0.0,
                0.0, 0.0, 1.0,
                0.0, 0.0, 0.0>
            matrix <
                1.0, 0.0, 0.0,  // Shear in x by y
                0.9, 1.0, 0.0,
                0.0, 0.0, 1.0,
                0.0, 0.0, 0.0>
#else
            matrix <  // Singular matrix parse error if shear 1x1
                1.0, 1.0, 0.0,  // Shear in y by x
                0.9, 1.0, 0.0,
                0.0, 0.0, 1.0,
                0.0, 0.0, 0.0>
#end
            scale 1/6
#end
        }
        finish { emission 1 }
    }
    camera { Camera01z }