A bending transformation (which is a nonlinear transformation) is not
possible for mathematical and technical reasons (see
http://www.students.tut.fi/~warp/povVFAQ/languageVFAQ.html#bending).

  You have many choices:

  You can use a torus section for a bended cylinder. A bended cone is harder
(can't be done with existing primitives, at least not perfectly).

  You can make isosurfaces. All those objects should be possible with them,
but it will require quite a lot of math knowledge.

  You can make them with a mesh of smooth triangles. You still need some
math, but probably not as much as with isosurfaces.
  This solution is not as bad is it might sound. You can use LOTS of triangles
to make the shape (so that you don't get visible straight line segments in
the silhouette of the object) without the rendering slowing down (but of
course memory usage will increase).

  You can make them with bicubic patches. The result is exactly the same
as with the mesh of smooth triangles, but the advantage is that you can
more easily control the resolution of the mesh.
  The disadvantage is that you need more complicated math than with the mesh
(if it can be used as a reference, I myself know enough math to make the mesh
but not the bicubic patches for bended cylinders and cones).

-- 
main(i,_){for(_?--i,main(i+2,"FhhQHFIJD|FQTITFN]zRFHhhTBFHhhTBFysdB"[i]
):_;i&&_>1;printf("%s",_-70?_&1?"[]":" ":(_=0,"\n")),_/=2);} /*- Warp -*/

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