1.   Cumbersome microfilm reading machines were a hulking presence.

2.   Later, as the number of microfilm machines and garish yellow chairs multiplied, the room became dowdy.

3.   Once the microfilm machines and the yellow chairs were removed, the tables were returned to the room, updated with wiring for computers.

4.   So books were fed into the maw of the microfilm machine, and then tossed out.