Accordion spacer in an album - beautiful construction - A concertina em ação by Zoopress studio. This construction is very useful for books that will have photos attached to pages, to keep the book from getting thicker at the edge from the bulk.
A fully loaded workshop play space See there? You could disguise that and use it in a traditional room. What is it? It's a "floor sweep". Simply sweep the crap into the box and the dust collector sucks it up.