THE BASKETBALL
four FIBA sizes with their circumference and mass — and why the rules set a bounce, not a pressure
Free
FOOTBALL: THE BALL
Law 2, three codes of the game, five sizes and three FIFA quality marks — what a ball must survive
$2.50
IMPERIAL UNITS
convert in your head · without a calculator
Free
SI PREFIXES
from quetta to quecto · twenty multipliers
$1.50
BICYCLE CLASSES
frame, wheel by ISO 5775 and handlebar — three signs of a class, and what the frame is rated for
Free
CAR CLASSES
segments A to F by length and bodies by box count — how to name any car you see
Free
THE RACING LINE
one corner, three apexes, the time computed
Free