Reference charts
A reference sheet promises completeness within its subject. Every letter, every status code, every prefix, every phase — not a selection of the handy ones. That promise is what makes it worth wall space: you can stop wondering whether the answer is on there.
It is the largest kind in the catalogue and it runs across most of the subjects — alphabets and codes, the geography of instruments, the tea and coffee sheets, units and paper formats, the planets and the Moon.
Because they are dense, they reward the larger print. A3 is usually the right call for anything read from more than a metre away.
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
NUMBERS 1 TO 100
the hundred chart · primes picked out in colour
LEAP YEARS
one rule, a cycle of four hundred years and the ninety-seven extra days in it
MULTIPLICATION TABLE
1 to 12 · colour intensity = size of the product
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
BIT DEPTH
how many steps the level is cut into, what a bit adds, and why floating point is not the next row
CIRCLE OF FIFTHS
12 keys · key signatures · relative minors
CURWEN HAND SIGNS
one hand for each degree of the scale, with the mental effect John Curwen gave it
DECIBEL SCALES
what stands at zero on each of them, and why −10 and +4 are not fourteen apart