You can bake the normals of the low poly object and use that as a texture on the plane.  
With a Color Ramp you can change the colors of the normal map texture.

[![enter image description here][1]][1]

[How to bake in Cycles][2]


  [1]: https://i.sstatic.net/Pyo8o.png
  [2]: https://blender.stackexchange.com/questions/13508/how-do-i-bake-a-texture-using-cycles-bake