Guillotine glass gets its name from the way it opens and closes. In this mechanism a window is (usually) made of three glass tiles horizontally covered throughout the window. These horizontal tiles move vertically (like a guillotine) and make the window open or close. One of the tiles is fixed but the other two tiles are movable.
There are three methods for opening the guillotine glass:
1- fixed tile at bottom
2- fixed tile in middle
3- fixed tile at above