evaluate ($x_1 = $spacing * 0.721237 )
evaluate($y_1 = $spacing * -0.691085 )
evaluate($z_1 = $spacing   * 0.047104 )
evaluate ($x_2 = $spacing * -0.737369 )
evaluate($y_2 = $spacing * 0.000000 )
evaluate($z_2 = $spacing   * 0.675490 )
evaluate ($x_3 = $spacing * 0.016131 )
evaluate($y_3 = $spacing * 0.691085 )
evaluate($z_3 = $spacing   * -0.722594 )
