Yes, it’s from a book called “Uncle John’s Bathroom Reader” and that book was resting on a closed toilet seat in a nation that only kind of uses the metric system in certain situations… however, you’d be surprised how much you can learn after a single visit to any local fast-food joint!
The decimeter is certainly an overlooked unit, and it’s a shame it’s relegated to relative obscurity - I use it occasionally even if people give me weird looks. Ideally I think something in the range of 20-30cm would make for a nice base unit - about the length of a forearm. Deci-units around the length of a finger segment, and centi-units being a slightly larger millimetre-equivalent. A deca-unit would be about the height of a doorframe.