listen; there's a hell of a good universe next door: let's go.go theremore quotes

# algorithms: recursive

Scientific graphical abstracts — design guidelines

# data visualization + art

Like algorithms?
Enjoy even more $\\pi$ art.

# Hola Mundo and Hello $\pi$

Art is science in love.
— E.F. Weisslitz

Remix of the cover design of Hola Mundo by Hannah Fry. (zoom)
Remix of the cover design of Hola Mundo by Hannah Fry. (zoom)
Remix of the cover design of Hola Mundo by Hannah Fry. (zoom)

## art and algorithms

Some algorithms connect us and some keep us apart—we need them to remind us what it is to be human and what it is to be a computer.

My cover design for Hannah Fry's Hello World: Being Human in the Age of Algorithms is based on my 2013 $\pi$ Day art. The book is published by Blackie Books.

Hola Mundo by Hannah Fry. Translation by Francisco J. Ramos Mena. Published by Blackie Books. Cover design by Martin Krzywinski. The front cover of the book shows a network based on the first 1,418 digits of $\pi$. (zoom)
Hola Mundo by Hannah Fry. Translation by Francisco J. Ramos Mena. Published by Blackie Books. Cover design by Martin Krzywinski. The back cover of the book shows a network based on the first 837 digits of $\pi$. (zoom)

## creating the cover

The cover begins with a 57 × 35 matrix of 1,995 colored circles. Each circle encodes a digit of $\pi$, starting with 3.1415.... Inside each circle is a smaller circle whose color is based on the next digit. The radius of the inner circle is $1/\phi^2$ where $1/\phi = 0.618$ is the Golden Ratio.

The beginning of the cover design. 1,995 colored circles encode digits of $\pi$. (zoom)
Each circle has a smaller circle inside it that encodes the next digit. (zoom)

Once the circles are drawn, neighbouring circles that correspond to the same digit are connected with thick lines. The thickness of these lines is $t_0 = 3/(2\phi^2)$, relative to the outer circle radius. Circles that correspond to digits whose difference is $1$ or $-1$ are connected by a slightly thinner line with thickness $t_1 = t_0/\phi$.

Neighbouring identical digits are connected with thick lines. (zoom)
Neighbouring digits that are off by 1 are connected by thinner lines. (zoom)

More lines are drawn that connect digits with a larger difference, $|d| > 1$. The thickness for these lines is $t_d = t_0/\phi^{|d|}$. When all differences up to $|d| < 6$ are accounted for, we get a pleasant jumble of lines.

Neighbouring digits whose difference is greater than one are connected by progressively thinner lines. (zoom)
Circles representing the digits of $\pi$ with all lines connecting neighbouring digits. (zoom)

To accommodate the title and other text on the cover, the design was generated by avoiding drawing any circles within a certain distance of the text.

This way, the network of digits wraps around the text. In the final design, the front page has 1,418 digits and the back has 878 digits.

Hola Mundo by Hannah Fry. Translation by Francisco J. Ramos Mena. Cover design by Martin Krzywinski. (zoom)
Hola Mundo by Hannah Fry. Translation by Francisco J. Ramos Mena. Cover design by Martin Krzywinski. (zoom)

## cover remixes

### just the lines

Just the connecting lines. (zoom)
Triangle color is the average color of their corners. (zoom)
Inner circles punched out. (zoom)
Just the triangles. (zoom)

# Music for the Moon: Flunk's 'Down Here / Moon Above'

Sat 29-05-2021

The Sanctuary Project is a Lunar vault of science and art. It includes two fully sequenced human genomes, sequenced and assembled by us at Canada's Michael Smith Genome Sciences Centre.

The first disc includes a song composed by Flunk for the (eventual) trip to the Moon.

But how do you send sound to space? I describe the inspiration, process and art behind the work.

The song 'Down Here / Moon Above' from Flunk's new album History of Everything Ever is our song for space. It appears on the Sanctuary genome discs, which aim to send two fully sequenced human genomes to the Moon. (more)

# Happy 2021 $\pi$ Day—A forest of digits

Sun 14-03-2021

Celebrate $\pi$ Day (March 14th) and finally see the digits through the forest.

The 26th tree in the digit forest of $\pi$. Why is there a flower on the ground?. (details)

This year is full of botanical whimsy. A Lindenmayer system forest – deterministic but always changing. Feel free to stop and pick the flowers from the ground.

The first 46 digits of $\pi$ in 8 trees. There are so many more. (details)

And things can get crazy in the forest.

A forest of the digits of '\pi$, by ecosystem. (details) Check out art from previous years: 2013$\pi$Day and 2014$\pi$Day, 2015$\pi$Day, 2016$\pi$Day, 2017$\pi$Day, 2018$\pi$Day and 2019$\pi` Day.

# Testing for rare conditions

Sun 30-05-2021

All that glitters is not gold. —W. Shakespeare

The sensitivity and specificity of a test do not necessarily correspond to its error rate. This becomes critically important when testing for a rare condition — a test with 99% sensitivity and specificity has an even chance of being wrong when the condition prevalence is 1%.

We discuss the positive predictive value (PPV) and how practices such as screen can increase it.

Nature Methods Points of Significance column: Testing for rare conditions. (read)

Altman, N. & Krzywinski, M. (2021) Points of significance: Testing for rare conditions. Nature Methods 18:224–225.

# Standardization fallacy

Tue 09-02-2021

We demand rigidly defined areas of doubt and uncertainty! —D. Adams

A popular notion about experiments is that it's good to keep variability in subjects low to limit the influence of confounding factors. This is called standardization.

Unfortunately, although standardization increases power, it can induce unrealistically low variability and lead to results that do not generalize to the population of interest. And, in fact, may be irreproducible.

Nature Methods Points of Significance column: Standardization fallacy. (read)

Not paying attention to these details and thinking (or hoping) that standardization is always good is the "standardization fallacy". In this column, we look at how standardization can be balanced with heterogenization to avoid this thorny issue.

Voelkl, B., Würbel, H., Krzywinski, M. & Altman, N. (2021) Points of significance: Standardization fallacy. Nature Methods 18:5–6.

# Graphical Abstract Design Guidelines

Fri 13-11-2020

Clear, concise, legible and compelling.

Making a scientific graphical abstract? Refer to my practical design guidelines and redesign examples to improve organization, design and clarity of your graphical abstracts.

Graphical Abstract Design Guidelines — Clear, concise, legible and compelling.

# "This data might give you a migrane"

Tue 06-10-2020

An in-depth look at my process of reacting to a bad figure — how I design a poster and tell data stories.

A poster of high BMI and obesity prevalence for 185 countries.