Charts for a study
The wall beside a desk is prime reference space. Whatever hangs there gets consulted without a browser tab, without a search, and without the several minutes a search usually turns into.
What suits it is the material used mid-task: status codes and CSS properties, the working areas of Git, unit prefixes and paper formats, Morse and the phonetic alphabet, the Greek letters that turn up in every formula, and the size conversions wanted the moment something is ordered from abroad.
A4 is usually enough at desk distance. Print on white, on whatever printer is already in the room — that is what these files are built for.
MARKDOWN SYNTAX
headings, emphasis, lists, links and code per the CommonMark 0.31.2 specification — the core all dialects share
MEDIA TYPES
2322 registered subtypes under 11 top-level types, and how to read one you have never seen
THE FLAGS OF OPEN()
FIVE flags of creating a file — and why O_CREAT|O_EXCL is not a faster check but a check and a creation joined into one indivisible act
${…}: FOUR MODIFICATIONS
The colon asks about emptiness too: in the column of the empty variable it changes the answer four times out of four, and in the other two columns none
${…}: TRIMMING BY PATTERN
The sign says from which end to cut and doubling it says how much: from the same path the same pair of patterns takes away either one character or fifteen
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 ORDER OF REDIRECTIONS
Redirections are done from left to right, and “2>&1” copies where the output points at that very moment: the file first — and it holds two lines; the copy first — one
REGULAR EXPRESSIONS
anchors, classes, quantifiers and groups: what a pattern is made of and how it reads, token by token
TIMESTAMPS
date, time and offset from UTC in one string: what it is made of and what it is not
SEMANTIC VERSIONING
what each of the three numbers means, what may follow them, and the order versions stand in
QUOTING IN THE SHELL
29 characters named by the standard, 4 ways to take the meaning off them — and the 3 characters where double quotes stop
read: A LINE INTO VARIABLES
The last variable takes the whole rest of the line, inner spaces and all; without -r the backslash disappears, and a line with no final newline gives status 1 — although the variable is already full
INSERTION SORT
the way cards are ordered in the hand · the trace of one real run
QUICKSORT
splitting around a pivot · the trace of one real run
TWO-CAMERA SPEAKER SETUP
the lighting triangle and where each of the 2 cameras stands · the floor plan from above
THREE-CAMERA SPEAKER SETUP
the lighting triangle and where each of the 3 cameras stands · the floor plan from above
THE SELECT STATEMENT
8 clauses in the order you write them — and the order they take effect in
SUBNET MASKS
from /0 to /32: the mask, how many addresses a block holds, and how many of them go to hosts
THE CONDITIONS OF TRAP
FIVE conditions from the standard — EXIT and four signals — and three extensions a conformant shell refuses
THE UMASK
The file mode creation mask: the nine bits it clears, five arguments that name opposite things — and why umask 022 is not chmod 755
UML DIAGRAMS
the fourteen kinds, and the notation a class diagram is made of
THE UNICODE SPACE
1 114 112 code points in 17 planes: 159 866 characters, 137 468 private, 814 730 free
PERCENT-ENCODING IN URIs
128 ASCII positions: 66 unreserved, 18 delimiters, 43 that must always be encoded — and the "%" itself
THE UTF-8 ENCODING
how a Unicode code point falls into one, two, three or four bytes — and which bytes never appear
UUID
thirty-six characters: where the version sits, where the variant sits, and what each of the eight versions is made of
VIDEO CARRIERS
nine formats at true scale — and the frame that kept growing after the carrier stopped
VIDEO FORMATS
who published each standard, when, the names it goes by, and what has to be squeezed
VIM COMMANDS
modes, motions and editing per the Vim 9.1 help — and the grammar that composes them into commands
WORD EXPANSION
Four steps in a fixed order — and only two of them can change how many fields reach the command
ENGLISH PUNCTUATION
twelve marks and the three strokes: a name, a job and one working example for each
GREEK ALPHABET
24 letters · names and where science uses them
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
THE COLLATZ CONJECTURE
halve the even, triple the odd and add one: the road of 27, the record holders and a problem nobody has solved
THE DOOMSDAY RULE
the weekday of any date in the Gregorian calendar, worked out in the head in three steps
REPEATING DECIMALS
which fractions stop, which run for ever, and how to know the length of the repeat without dividing
THE RULE OF 72
the time it takes steady growth to double: the division you can do in your head, how far it misses and why the divisor is what it is
THE BEAUFORT SCALE
thirteen forces of wind — from water like a mirror to a wave of fourteen metres
COLOUR GAMUTS
sRGB, Display P3, Rec. 2020 and ProPhoto RGB on the CIE 1931 chromaticity diagram
THE COMPASS ROSE
the sixteen compass points with exact bearings: four cardinal, four intercardinal, eight in between
TN, VA, IPS AND OLED
what differs inside the cell · and a paper describing each mode
THE FUJITA SCALE
six categories of tornado damage — and the two different winds assigned to them
GREEK LETTERS IN SCIENCE
10 capitals with a shape of their own, 14 twins of Latin letters, and what each one stands for
USDA HARDINESS ZONES
the 13 zones by average annual extreme minimum — each range in °F and °C, with the a and b half-zones
THE MOMENT MAGNITUDE SCALE
what a single step hides: ×10 in recorded amplitude and roughly ×32 in released energy — drawn to true scale