NEEDLES AND YARN
knitting needle sizes in three systems — metric, old UK, US — and the 0–7 yarn weights per the Craft Yarn Council
US$1.50
THE LARGEST COUNTRIES
the ten largest by surface area — as squares at true scale, each inside the next
US$1.50
LEAP SECONDS
27 seconds added to UTC since 1972, none since 2016 — the longest run there has ever been
US$1.50
PAPER SIZES
the A series · from A0 to A6
US$1.50
PHOTO PRINT SIZES
how many millimetres each size really is, and how much of the frame goes under the knife
US$1.50
CAMERA SENSORS
seven sizes at one scale, with the crop factor computed from the diagonal
US$1.50
SI BASE UNITS
seven constants given an exact number — and the seven units that follow from them
US$1.50
SI DERIVED UNITS
twenty-two with names of their own — and what each one is made of
US$1.50
SI PREFIXES
from quetta to quecto · twenty multipliers
US$1.50
THE AMERICAN WIRE GAUGE
forty-four sizes derived from two diameters and one law of progression
US$1.50