Lottery winners press the pause button (mostly the space bar) of the computer in turn. When scrolling stops, what unit, floor and room number are displayed, which is the house drawn by lottery winners.
This kind of computer lottery is very random, and the floor and orientation of the house are not necessarily what you like, either which floor you want or which floor you want, depending on your luck.
Of course, for everyone, this is a fairer way to draw lots.