Transform {
  translation -1.5 -1.5 0
  children [
          Shape { 
                  geometry DEF nurb NurbsSurface {
                          #uOrder 4 
                          #vOrder 4 
                          uDimension 4 
                          vDimension 4 
                          #uKnot [ 0, 0, 0, 0, 3, 3, 3, 3]
                          #vKnot [ 0, 0, 0, 0, 3, 3, 3, 3]
  
                          controlPoint[
                                  0 -0.5 0, 1 0.5 0, 2 -0.5 0, 3 0.5 0,
                                  #0 0 0, 1 0 0, 2 0 0, 3 0 0,
                                  0 1 0, 1 1 0, 2 1 0, 3 1 0, 
                                  0 2 0, 1 2 0, 2 2 0, 3 2 0, 
                                  0 3 0, 1 3 0, 2 3 0, 3 3 0]
  
                          }