// linear prism in y-direction: from .. ,to ..,number of points (first = last)
prism { linear_sweep
        cubic_spline
        0.00 ,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<-1.0,0,0> 
      } // end of prism --------------------------------------------------------

// linear prism in y-direction: from .. ,to ..,number of points (first = last)
prism { conic_sweep
        cubic_spline
        0.00 ,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<0,2.00,0>    // turn arround !!!
        rotate<0,0,0>
        translate<0.2,0,0> 
      } // end of prism --------------------------------------------------------


// linear prism in y-direction: from .. ,to ..,number of points (first = last)
prism { conic_sweep
        cubic_spline
        0.00 ,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<1.0,0,0> 
      } // end of prism --------------------------------------------------------