I use a variety of swiveling office chairs, which must each rotate by a few hundred*Pi radians each day.
In order to make some use of this spinning, today’s invention is a coffee bean grinder which can be fitted to any such seat.
It consists of an annular can which fits over the central axis of the base (by detaching the seat) and which has a hatch into which beans may be poured. At the bottom of the can, another hatch with a chute allows the ground coffee to be tapped into one’s cafetiere.
The seat is equipped with a fixed arm on the end of which is a roller. This wheel penetrates the annular lid of the bean can and, as the seat rotates relative to the base, so the roller grinds the beans.
This makes a graunching noise, but fills the office with a lovely aroma. A more advanced version would allow hot water to be added to an integrated cafetiere.