A tour of coppice

This post is a sampler. Each section below shows one thing a coppice site can do, working, rather than describing it; Writing with coppice has the syntax behind each. Because the post has several sections, it has a contents list, unless contents is turned off in config.toml: on a wide screen it is the sidebar on the left, marking the section you are reading, and on a narrow one it is the list above.

Notes in the margin

Long asides interrupt an argument, and footnotes make readers jump to the bottom of the page and back. Sidenotes sit beside the line they belong to instead.This is a sidenote. On a wide screen it sits in the right margin, level with its number; on a narrow one, tap the number to open it under the line. They are numbered in order through the post.The second one. Notes can hold markdown, and links too. A margin note is the same without a number, for a remark rather than a reference.⊕A margin note: on a narrow screen it opens from the ⊕.

In the feed, which has no margins, each note follows its line in parentheses, so nothing is lost there either.

Type

Text is set in one column, with italics, bold, struck-out words, inline code and links. Headings come in three levels below the title.

A third-level heading

And a fourth

A quotation stands apart, in italics, with a rule down its left side, and its source underneath.

Lists come numbered, bulleted or ticked:

1. Write in markdown.
2. Run go run ..
3. Upload public/.

• sidenotes
• galleries
• a newsletter

Tables

Tables take the column's width, with figures lined up. These are the thirteen animations the home page can show, set by animation in config.toml:

animation	what it draws
shapes	ASCII solids that melt into each other: a donut, a cube, a Menger sponge
curve	Lissajous figures and rose curves, one line throughout
cycloid	a circle rolling round another: cardioid, nephroid, astroid
cycloid-horizontal	a circle rolling along a line: normal, curtate and prolate cycloids
medley	curve, cycloid and cycloid-horizontal as one
mandelbrot	one line closing in on the Mandelbrot set's boundary
ford	Ford circles over the fractions from 0 to 1
golden	a line that curls into the golden spiral and back
nautilus	a nautilus shell in section, its chambers growing in
sine	a pen bobbing up and down, its height drawn out as a sine wave
penrose	the impossible triangle, turning for ever
chords	chords round a circle, their envelope a cardioid, then a nephroid
newton	Newton's cradle

On a narrow screen a table too wide for it scrolls sideways.

Code

Code is highlighted when the site is built, so readers download no highlighter, and each block has a button to copy it. The ratio of neighbouring Fibonacci numbers closes in on the golden ratio, the one the golden animation curls into:

package main

import (
	"fmt"
	"math"
)

func main() {
	a, b := 1.0, 1.0
	for range 20 {
		a, b = b, a+b
	}
	fmt.Printf("F(22)/F(21) = %.10f\n", b/a)
	fmt.Printf("φ           = %.10f\n", (1+math.Sqrt(5))/2)
}

It prints 1.6180339850 and 1.6180339887: twenty steps get eight decimal places right. The ford animation draws one circle for every fraction between 0 and 1 whose denominator is at most 20:

from math import gcd

fractions = [(p, q) for q in range(1, 21) for p in range(q + 1) if gcd(p, q) == 1]
print(len(fractions), "circles")
print("smallest radius:", 1 / (2 * 20**2))

It finds 129 circles, the smallest of radius 0.00125, when the two largest have radius ½.

Mathematics

Equations are MathML, drawn by the browser itself, with no script and no pictures of formulae. The circle over the fraction p/q has radius 1/(2q²), and two of them touch exactly when the fractions are neighbours:

$$|ps-qr|=1$$

for circles over p/q and r/s. And the sum Euler found in 1734:

$$\sum _{n=1}^{\infty }\frac{1}{n^2}=\frac{{\pi }^2}{6}$$

Pictures

A picture can carry a caption, set in a smaller, quieter type:

A gallery

A gallery works in a post as it does on a page: tiles in a grid, each opening larger over the page, with the arrow keys and Esc to move through them. These are six of the home page's animations, recorded as GIFs, in a gallery of columns, which shows each picture whole:

The gallery page has a hundred and eighteen paintings and prints, from van Eyck to Malevich.

Colours and type

Everything here follows config.toml. Ten colour themes, each with a light and a dark side that follow the reader's system: paper, Catppuccin, Gruvbox, Solarized, Nord, Rosé Pine, Tokyo Night, Everforest, Dracula and clrs. Ten styles for code, paired the same way. Any two fonts from Google Fonts, which the build downloads so that readers never contact Google; by default Atkinson Hyperlegible, drawn for readers with low vision. The site's own words in lowercase, as typed, in capitals or in small capitals. And a size for every kind of text, from this paragraph to the captions.