I was considering starting a new node for "Cinder block bookshelf", but I can probably include the relevant information here.
Along with being of great use in official construction projects, cinder blocks can also be used for building ad-hoc conveniences around the home and yard. Perhaps the exemplar of this is the cinder block book shelf, a simple contrivance where cinder blocks and boards are used to make a simple but effective bookshelf.
_______
8__8__8
8__8__8
8 8 8
With the "8"'s representing the cinder blocks, the underscores representing the boards, and the vertical spaces between the "8"'s representing the limitations of ASCII art. The cinder block bookshelf suggests a certain ambience and attitude, a working class bohemian aesthetic, as if to announce that even if you own a copy of Richard Ellman's biography of James Joyce, you are keeping it on something whose construction materials cost between $0 and $10. Other structures can be easily imagined and quickly constructed out of cinder blocks, with similar savings and bohemian messages sent.
Just be careful where you get your cinder blocks from, lest, like Homer Simpson, you inadvertently ruin the construction of a children's hospital.