// interpolate the triangle's texture between 3
// specified textures for the 3 vertices
mesh {
  triangle {
    <-1,  0, -1>, < 1,  0, -1>, < 0,  0,  1>    // vertices
    texture_list {
      Texture_01           // 3 previously declared textures
      Texture_02
      Texture_03
    }
  }
}