Well, I'm not sure what your aim is but I assume you are trying to add more geometric detail to the surface. If this is the case then there are a range of techniques for drawing a single polygon but then adding detail via a heightmap texture. It's a big field, but you could start by looking at this article:
http://http.developer.nvidia.com/GPUGems3/gpugems3_ch18.htmlIn particular, in figure 18-11 a simple cube is being drawn, but the geometry looks a lot more complex:
I'm not about your level of graphics knowledge but it's a fairly advanced technique. Note that that is just one of probably hundreds of papers describing similar techniques. You can also google for normal mapping, relief mapping, parallax mapping, displacement mapping for variations on a similar idea. I haven't implemented them myself, though.