CONSTELLATIONS BY SEASON
the northern evening sky through the year: 28 constellations per the Yale Bright Star Catalogue, latitude 40° N, evenings near 9 pm
METEOR SHOWERS
the twelve principal showers of the year · periods, peaks and ZHR per the IMO calendar
MARS
size, distances and time — computed from rotation, orbit and mass
SPRING AND NEAP TIDES
the Earth–moon–sun geometry that makes the tides swing — after NOAA
BLOOD PRESSURE CATEGORIES
the six AHA categories · 2025 guideline · the higher of the two readings decides
CPR AND CHOKING
the 2025 American Heart Association algorithms, step by step — bystander, trained rescuer, and choking at three ages
DRESS CODES
six lines that turn up on an invitation, and what each one actually asks for — after Debrett’s
THREE HAND STITCHES
backstitch · running stitch · whipstitch — what shows on the face and what the thread does underneath
THE CHILD IMMUNIZATION SCHEDULE
Table 1 of the CDC schedule, by age: all twenty rows from birth to 18 years, United States, 2025
LAUNDRY CARE SYMBOLS
the 28 symbols of the everyday clothing tag per ISO 3758:2023: five treatments in a fixed order, sharing one set of modifiers
MAGNESIUM COMPOUNDS
the share of magnesium in the salt, computed from the formula · and what human trials measured
NAIL SHAPES
eight shapes at one scale · what tells them apart in millimetres
SIZE CHARTS
shoes, tops, bottoms — and a centimetre under every grid
SERUM ACTIVES
when to apply, what to keep apart in time, what the season changes
THE STAGES OF SLEEP
light, deep and REM as honest shares of the night — and the 90–110 minute cycles it is built from
STAIN REMOVAL
five stain classes and the method for each — per publication H.E. 2-840 of the University of Kentucky Cooperative Extension
AI MILESTONES
ten tasks, the year of each, the system, the figure — and the human it was measured against
THE ASCII TABLE
all 128 positions: the column is the three high bits, the row is the four low ones
AUDIO FORMATS
who published each standard, when, what it does to the sound, and how many bits per second it allows
THE BASE32 ENCODING
forty bits to a quantum: five bytes, eight characters and five padding cases
THE BASE64 ENCODING
three bytes become four characters: the alphabet, the tail, and what the "=" at the end is for
BIG-O NOTATION
the seven growth classes: how many steps, how long they take and how far each one lets you go
THE CRON EXPRESSION
the five schedule fields: what each one means, what values it takes, and how to read stars, lists and steps
CSS GRID
the container properties and the item properties per the css-grid-2 specification — and what each does to the layout