Berkeley has roughly 50 official little free libraries and dozens more unofficial ones — and the most interesting have quietly expanded well past books, into CDs, jigsaw puzzles, miniature art and banned titles.

At 900 Bancroft Way in West Berkeley, a sidewalk library holds no books at all. Instead, Phil Rowntree stocks it with cassette tapes, CDs, DVDs and VHS tapes — old-school media he encounters as an eBay reseller, functional but unsellable. He started it, he told Berkeleyside, to "try and find homes for recorded media that could otherwise end up in the landfill." Anyone with a large collection to donate can reach him directly.

That's one of roughly 50 official little free libraries scattered across Berkeley, with dozens more operating without a charter plaque, according to a survey published July 6 by Berkeleyside reporter Hope Muñoz. The official ones are registered with Little Free Library, the nonprofit launched in 2009 in Hudson, Wisconsin. Berkeley's unofficial ones have largely gone their own way.

The 12 Muñoz identified span the city's residential blocks with a specificity that doubles as a neighborhood inventory. At 2410 Browning St., the offering is jigsaw puzzles — difficulty ranging from under 50 pieces to 1,000 or more, take or swap. At 3115 Eton Ave., someone retrofitted an old coin-operated newspaper vending machine, sized for kids, PG titles only. (A side note in the article: that style of vending machine was invented in Berkeley.) At 2337 Derby St., a diorama museum with 13 display windows lets visitors submit their own miniature scenes through the library's website. At 2000 Yolo Ave., banned books — defined by Little Free Library as titles removed from American schools — share a roof with succulents growing from the structure's top.

The art-adjacent entries multiply from there. A double-installation at 1620 California St. stacks a miniature art exchange on top of a keychain swap. A tiny showcase at 1342 Hopkins St. currently displays a community-built protest piece: residents brought action figures and wrote on blank signs the creator supplied. At 363 Panoramic Way, the cabinet itself is a reclaim — found at Urban Ore.

What none of these structures required was a building permit. They sit on the sidewalk, ungoverned, maintained by whoever put them there. The Little Free Library nonprofit's charter system gives registered ones a number and a spot on the official global map — 50 states, 128 countries, seven continents — but it doesn't govern content or form. Berkeley's most inventive exhibits seem to have concluded that wasn't a constraint worth keeping.

The disk and tape library at 900 Bancroft is taking donations.