IMPERIAL UNITS
convert in your head · without a calculator
Free
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
Free
APERTURE, SHUTTER, ISO
one stop is twice the light: three scales with the same step on each
Free
SI UNITS WITHOUT NAMES
the endless rest: assembled from the base and the named units, and never with a factor
Free
THE TALLEST BUILDINGS
the ten tallest at true scale — and where the floors in them end
Free
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
Free