NEEDLES AND YARN
knitting needle sizes in three systems — metric, old UK, US — and the 0–7 yarn weights per the Craft Yarn Council
THE LARGEST COUNTRIES
the ten largest by surface area — as squares at true scale, each inside the next
LEAP SECONDS
27 seconds added to UTC since 1972, none since 2016 — the longest run there has ever been
PAPER SIZES
the A series · from A0 to A6
PHOTO PRINT SIZES
how many millimetres each size really is, and how much of the frame goes under the knife
CAMERA SENSORS
seven sizes at one scale, with the crop factor computed from the diagonal
SI BASE UNITS
seven constants given an exact number — and the seven units that follow from them
SI DERIVED UNITS
twenty-two with names of their own — and what each one is made of
SI PREFIXES
from quetta to quecto · twenty multipliers
THE AMERICAN WIRE GAUGE
forty-four sizes derived from two diameters and one law of progression
PETROL AND DIESEL
nine lines of comparison, and in three of them the requirement is the same for both