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Distractions and amusements, with a sandwich and coffee.

music + dance + projected visuals
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On March 14th celebrate `\pi` Day. Hug `\pi`—find a way to do it.

For those who favour `\tau=2\pi` will have to postpone celebrations until July 26th. That's what you get for thinking that `\pi` is wrong. I sympathize with this position and have `\tau` day art too!

If you're not into details, you may opt to party on July 22nd, which is `\pi` approximation day (`\pi` ≈ 22/7). It's 20% more accurate that the official `\pi` day!

Finally, if you believe that `\pi = 3`, you should read why `\pi` is not equal to 3.

2013 was the first year in which I made `\pi` day art. It was a year of dots and love.

René Hansen has created an interactive version of this year's posters! Why not go to the Feynman point directly!

All the posters are also available without the "`\pi` day 3 · 14" inscription.

`\pi_i` / grey 80% opacity

`\pi_i`/`\pi_{i+1}` 80% opacity

`\pi_i` / grey 80% opacity (equal neighbours connected)

`\pi_i` / `\pi_{i+1}` 80% opacity (equal neighbours connected)

— / `\pi_{i+1}` (equal neighbours connected, unconnected digits not shown)

`\pi_i` / `\pi_{i+1}` (equal neighbours connected with line width proportional to difference in neighbour digits `d in \{0,1,2\}`, unconnected digits not shown)

`\pi_i` / `\pi_{i+1}` (equal neighbours connected with line width proportional to difference in neighbour digits `d in \{0...5\}`, unconnected digits not shown)

`\pi` : — / red (equal neighbours connected, unconnected digits not shown)

`\phi` : — / white (equal neighbours connected, unconnected digits not shown)

`e` : — / grey (equal neighbours connected, unconnected digits not shown)

`\pi_i` / grey 80% opacity (equal neighbours connected)

`\pi_i` / `\pi_{i+1}` 80% opacity (equal neighbours connected)

`\pi_i` / grey 80% opacity (equal neighbours connected, unconnected digits not shown)

`\pi_i` / `\pi_{i+1}` 80% opacity (equal neighbours connected, unconnected digits not shown)

As part of the COVID Charts series, I fix a muddled and storyless graphic tweeted by Adrian Dix, Canada's Health Minister.

I show you how to fix color schemes to make them colorblind-accessible and effective in revealing patters, how to reduce redundancy in labels (a key but overlooked part of many visualizations) and how to extract a story out of a table to frame the narrative.

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.

A forest of digits

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

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.

And things can get crazy in the forest.

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.

*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.

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

*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.

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.

*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.