union{
// linear prism in y-direction: from .. ,to ..,number of points (first = last)
prism { linear_sweep
        linear_spline
        0.50 ,1.00 , 6
        <-0.50, 0.00>, < 0.50,  0.00>, < 0.00,-0.75>, <-0.50, 0.00>,
        < 0.50, 0.00>, < 0.00, -0.75>
        texture {pigment{ color White}
                 finish { phong 1.0}}
        rotate<0,-20,0>
        translate<-1.2,0,0>
      } // end of prism --------------------------------------------------------

// linear prism in y-direction: from .. ,to ..,number of points (first = last)
prism { conic_sweep
        linear_spline
        0.50 ,1.00 , 6
        <-0.50, 0.00>, < 0.50,  0.00>, < 0.00,-0.75>, <-0.50, 0.00>,
        < 0.50, 0.00>, < 0.00, -0.75>
        texture {pigment{ color White}
                 finish { phong 1.0}}
        rotate<0,0,0>
        translate<0,0,0>
      } // end of prism --------------------------------------------------------


// linear prism in y-direction: from .. ,to ..,number of points (first = last)
prism { conic_sweep
        linear_spline
        0.50 ,1.00 , 6
        <-0.50, 0.00>, < 0.50,  0.00>, < 0.00,-0.75>, <-0.50, 0.00>,
        < 0.50, 0.00>, < 0.00, -0.75>
        texture {pigment{ color White}
                 finish { phong 1.0}}
        scale <1,-1,1> translate<0,1.00,0>    // turn arround !!!
        rotate<0,0,0>
        translate<1.2,0.50,0>
      } // end of prism --------------------------------------------------------
scale  1.1
rotate<-15,0,0>
} // end union