IMPERIAL UNITS
convert in your head · without a calculator
CURRENCY MINOR UNITS
178 codes in the standard: 139 currencies divide by 100, 17 do not divide at all, 7 divide by 1,000 — and 25 codes are not money you can spend
APERTURE, SHUTTER, ISO
one stop is twice the light: three scales with the same step on each
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 UNITS WITHOUT NAMES
the endless rest: assembled from the base and the named units, and never with a factor
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 TALLEST BUILDINGS
the ten tallest at true scale — and where the floors in them end
THE WORLD'S TIME OFFSETS
37 offsets from UTC−11:00 to UTC+14:00 — a spread of 25 hours over a 24-hour day
THE AMERICAN WIRE GAUGE
forty-four sizes derived from two diameters and one law of progression