The next few sections explain how to display the VSprites. The following
system functions are used:

    drawglist()  draws the vsprites into the current rastport.
       mrgcop()  installs the vsprites into the display.
     loadview()  asks the system to display the new view.
      waittof()  synchronizes the functions with the display.

 drawing the graphics elements    loading the new view 
 merging vsprite instructions     synchronizing with the display