I had a friend who worked at a paper mill where they made facial tissue - an interfolded product.

The process was interesting. Paper was made and spooled onto large and long rolls (8ft long cylinders if I recall). This was 40 years ago, so I don't recall the entire process. I think that after they ran the large roll down, they split the small diameter roll into tissue long axis length rolls. Then, a bunch of these rols were put onto a machine with as many rolls as there are tissues in a box. This giant machine had the rolls feed the area where the rolls were interfolded and when the stack proceeded down the line it got to a slicer and then the box was folded and glued around the stack. Never saw it in operation, but was interesting even sitting there...