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Photo: pinterest.com ANSWER It's the inside of an old fashioned Cylindrical (planetary) pencil sharpener!" Cylindrical Sharpeners A wall-mounted planetary sharpener (casing removed to reveal the mechanism). A larger, stationary mechanical sharpener can be mounted on a desk or wall and powered by a crank. Typically, the pencil is inserted into the sharpener with one hand and the crank turned with the other. This rotates a set of helical cylindrical cutters in the mechanism, set at a diverging angle to each other. This quickly sharpens the pencil, with a more precise finish than the simpler blade device. Advanced models have a spring-driven holder for the pencil (the pencil advances into the mechanism while being sharpened). Some versions also offer a regulator of the desired sharpness (it is not always desired to make the graphite core needle-sharp). Such sharpeners may be very easy to use even by children, but may be more expensive than prism sharpeners. Some such rotary sharpeners have only one burr cylinder. The casing of the sharpener is the repository for the pencil shavings, and needs to be emptied periodically. These mechanisms are also called planetary sharpeners, in reference to their use of planetary gears. Credit: wikipedia.com