More paper and correspondence drove the need for more complex desks and more specialized desks, such as the rolltop desk which was a mass-produced, slatted variant of the classical cylinder desk.[10] It provided a relatively fast and cheap way to lock up the ever increasing flow of paperwork without having to file everything by the end of the day. Paper documents became voluminous enough to be stored separately in filing cabinets. Correspondence and other documents were now too numerous to get enough attention to be rolled up or folded again, then summarized and tagged before being pigeonholed in a small compartment over or under the work surface of the desk.