DirectDraw example program 3.  

Adds functionality to example program 2.  Creates two offscreen surfaces in 
addition to the primary surface and back buffer.  Loads a bitmap file into 
each offscreen surface.  Uses BltFast to copy the contents of an offscreen 
surface to the back buffer and then flips the buffers and copies the next 
offscreen surface to the back buffer.  

This program requires at least 1.2 Megs of video ram.