 Usage:  pnew = nnvisu (d, pold)  
 
 Input:

  d                      n x 3 matrix of distances 
                         
  pold                   m x 2 starting position 
                         
 Output:

  pnew                   m x 2 computed new positions 
                         
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(C) MD*TECH Method and Data Technologies, 17.8.2000
