Abroad-leaf aquarium plant with rippled leaves

In[2]:=
  Clear[width,spine,ripple,normalize,tangent,normal,
    binormal]
  Needs["Calculus`VectorAnalysis`"];
  width[z_] = 0.2 z (1-z^3);
  spine[z_] = {0.05 z, 0.05 z, z};
  ripple[z_] = 0.01 Sin[20 Pi z];
  normalize[v_] = v/Sqrt[v.v];
  tangent[z_] = normalize[spine'[z]];
  binormal[z_] =
    normalize[CrossProduct[tangent[z], {0,1,0}]];
  normal[z_] = CrossProduct[tangent[z], binormal[z]];
  seaweed =
    ParametricPlot3D[
      spine[z] + y width[z] normal[z] +
                 y^2 ripple[z] binormal[z],
    {y,-1,1}, {z,0,1},
    PlotPoints -> {8,80}, ViewPoint -> {2,1,0}];

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