These cubby components are configurable in many different ways. Shown is one set of components that created three shelves (or you might way 1 surface and two shelves above). Includes a bag of about 30 sides and many connectors.
They are opaque/translucent. Relatively strong -- would surely hold paperbacks but I'm not sure about hardbound books. Great for stuffed animals and other things that kids collect.
You can make 2 up and 3 across, or 3 by 3, or a step-style unit of 1-2-3, or many other configurations. These belonged to my sister who has moved out of state.
Close in town, off Nevada City Highway behind SaveMart shopping center near Brunswick.