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
PHASES OF THE MOON
eight phases · a full cycle of 29.53 days
THE NAMES OF THE ASANAS
twenty foundational poses: Sanskrit, the searchable spelling, the English name — and how old each one is
BLOOD PRESSURE CATEGORIES
the six AHA categories · 2025 guideline · the higher of the two readings decides
DRESS CODES
six lines that turn up on an invitation, and what each one actually asks for — after Debrett’s
THE CHILD IMMUNIZATION SCHEDULE
Table 1 of the CDC schedule, by age: all twenty rows from birth to 18 years, United States, 2025
MAGNESIUM COMPOUNDS
the share of magnesium in the salt, computed from the formula · and what human trials measured
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
CSS GRID
the container properties and the item properties per the css-grid-2 specification — and what each does to the layout
BITS, BYTES, KILOBYTES
two scales · 1000 and 1024 · why a drive looks smaller
THE DMX512 PROTOCOL
512 channels down one serial wire, and why a full universe cannot refresh faster than 44 times a second
EAN-13
how thirteen digits become 95 modules of bars and spaces
FLOWCHART SYMBOLS
10 shapes, and one algorithm drawn with them
GO vs RUST
seven questions, the same to both, and the document each answer is written in
HTTP STATUS CODES
five classes · twenty codes you meet every day
JAVASCRIPT vs GO
seven questions, the same to both, and the document each answer is written in
JAVASCRIPT vs RUST
seven questions, the same to both, and the document each answer is written in
LANGUAGE CODES
487 rows in ISO 639-2; 183 languages also have a two-letter code and 20 have two three-letter ones — and the tag is always the shortest
LIFE CYCLE MODELS
the same steps arranged five ways: the document, the year, and what one turn of the loop covers
THE MIDI PROTOCOL
one top bit separates status from data, seven commands per channel, and how much time a serial wire actually takes
POSIX SIGNALS
Twenty-seven signals, five default actions — and two that cannot be caught, ignored or blocked
PYTHON vs GO
seven questions, the same to both, and the document each answer is written in
PYTHON vs JAVASCRIPT
seven questions, the same to both, and the document each answer is written in
PYTHON vs RUST
seven questions, the same to both, and the document each answer is written in
THE UNICODE SPACE
1 114 112 code points in 17 planes: 159 866 characters, 137 468 private, 814 730 free
UUID
thirty-six characters: where the version sits, where the variant sits, and what each of the eight versions is made of
VIDEO FORMATS
who published each standard, when, the names it goes by, and what has to be squeezed
POST-FERMENTED TEAS
six teas changed by microbes rather than oxygen
PUERH AGEING
sheng and shu · what the years do and when to drink
BLACK TEA
grades, six leaves and four blends · in China it is "red tea"
GREEN TEA
six leaves · water, time, number of steepings
OOLONG
from 15 to 80 % oxidation · leaf shape · seven steepings
SIX KINDS OF TEA
one plant · the oxidation scale · seven processing steps
ENGLISH ALPHABET
26 letters · 5 vowels · 21 consonants
GREEK ALPHABET
24 letters · names and where science uses them
IRREGULAR VERBS
the 100 you meet most: base · past · past participle — grouped by the four patterns, not shuffled alphabetically
LETTER TEAMS
40 letter combinations and the sounds they spell, in IPA, with one example word each
SIGHT WORDS
all 220 Dolch service words in five grade groups, Pre-K through third — with the top of the Fry frequency list up front
BENFORD’S LAW
the first digit of a number: why a one turns up more than six times as often as a nine, and in which sets that is true
THE BIRTHDAY PARADOX
how many people it takes for two of them to share a birthday — and the same count for codes and fingerprints
PASCAL’S TRIANGLE
the first thirteen rows, the sum of each row and the pattern of the odd numbers
REPEATING DECIMALS
which fractions stop, which run for ever, and how to know the length of the repeat without dividing
ROMAN NUMERALS
seven symbols · ones, tens, hundreds · years
AUDIO CONNECTORS
analog, digital, and speaker wiring · pinouts and balanced signals
DECIBEL SCALES
what stands at zero on each of them, and why −10 and +4 are not fourteen apart
INSTRUMENT FREQUENCIES
fundamentals and overtones · 20 Hz – 20 kHz, logarithmic scale