lower , the x coordinate must start from zero to 1, x/c , z/c where c is the cord length
  0.000000  0.000000
  0.002223 -0.006689
  0.007479 -0.012828
  0.015723 -0.018404
  0.026892 -0.023408
  0.040906 -0.027826
  0.057669 -0.031651
  0.077071 -0.034878
  0.098987 -0.037507
  0.123281 -0.039546
  0.149805 -0.041013
  0.178401 -0.041934
  0.208902 -0.042346
  0.241131 -0.042294
  0.274904 -0.041834
  0.310028 -0.041027
  0.346303 -0.039941
  0.383522 -0.038644
  0.421644 -0.037174
  0.460397 -0.035444
  0.499412 -0.033493
  0.538451 -0.031373
  0.577279 -0.029138
  0.615658 -0.026833
  0.653352 -0.024500
  0.690129 -0.022172
  0.725762 -0.019880
  0.760029 -0.017649
  0.792716 -0.015499
  0.823619 -0.013448
  0.852541 -0.011510
  0.879302 -0.009701
  0.903730 -0.008033
  0.925669 -0.006520
  0.944979 -0.005174
  0.961536 -0.004008
  0.975232 -0.003035
  0.985978 -0.002265
  0.993705 -0.001708
  0.998361 -0.001370
  0.999916 -0.001257
lower
