D3DPT_TRIANGLESTRIP Rendering Flag
Here i gonna show you for what is the
D3DPT_TRIANGLESTRIP Rendering Flag:
This flag Tells to Direct3DDevice that you are passing
a vertex list that gives as result a ZigZag Line,
here i try to explaint it with more detail:

If you see, we need to Declare Only 4 Vertex for
2 Tringles, with this flag Direct3D automatically completes
a tringle on a zigzag vertex list, This is the usefulest flag
of all couse it saves a lot of space but also haves his
limitations, like you can't separate the triangles.