evaluate ($x_1 = $spacing * 0.630514 )
evaluate($y_1 = $spacing * -0.775711 )
evaluate($z_1 = $spacing   * 0.026929 )
evaluate ($x_2 = $spacing * -0.860987 )
evaluate($y_2 = $spacing * -0.254834 )
evaluate($z_2 = $spacing   * 0.440184 )
evaluate ($x_3 = $spacing * -0.174528 )
evaluate($y_3 = $spacing * 0.254834 )
evaluate($z_3 = $spacing   * -0.951104 )
evaluate ($x_4 = $spacing * 0.405000 )
evaluate($y_4 = $spacing * 0.775711 )
evaluate($z_4 = $spacing   * 0.483991 )
