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`\pi` Day 2015 Art Posters
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.
Not a circle in sight in the 2015 `\pi` day art. Try to figure out how up to 612,330 digits are encoded before reading about the method. `\pi`'s transcendental friends `\phi` and `e` are there too—golden and natural. Get it?
This year's `\pi` day is particularly special. The digits of time specify a precise time if the date is encoded in North American day-month-year convention: 3-14-15 9:26:53.
The art has been featured in Ana Swanson's Wonkblog article at the Washington Post—10 Stunning Images Show The Beauty Hidden in `\pi`.
I find this image deeply beautiful and deeply troubling, and I’ll try to explain why. —Max Cooper
The 7-level tree map was used for the Transcendental Tree Map track on Max Cooper's Yearning for the Infinite album. The album is an “audio/visual rendering with our obsession with the unobtainable”.
The video for the track was a collaboration between myself and Nick Cobby. The music contains layered loops whose lengths are based on prime numbers—as the track plays, some loops individually come in and out of phase with others, forming a longer loop. The full set never synchronizes though.
The transcendental tree map encodes the first 20,244 digits of `\pi` = 3.1415...7012.
creating the video
The video constructs and then chaotically deconstructs a 7 level tree map of the digits of `\pi`. This map is shown below and is similar to other images I made for 2015 Pi Day, except that here the map is formatted for a 16:9 screen.
The video starts with an explicit construction of the map. This process begins with dividing the canvas with 3 vertical lines, which forms 4 rectangles. Each of the four rectangles formed by this process is divided with 1, 4, 1 and 5 horizontal lines, respectively. This forms 2 + 5 + 2 + 6 = 15 rectangles. Each of the 15 rectangles is divided by vertical lines according to the next 15 digits of Pi. This process repeats until we have performed the loop 7 times.
The division of each rectangle is not even—the positions of the lines are slightly jittered. This gives the map a more organic feel.
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The number of digits encoded in each loop is 1, 4, 15, 98, 548, 2,962 and 16,616. In total, 17,180 vertical and 3,064 horizontal lines are drawn and these form the backbone of the map.
The video is created by layering numerous animations of the construction of the map, in which the rate and order of line growth is varied. Blinking rectangles indicate that the lines for a digit have completed drawing.
Chromosomes — music, genomes, split-flaps
A short electronic music concert based on structures of chromosomes 21, Y and 1.
Each track uses a microtonal scale derived from the cytogenetic band positions of the chromosome. Rhythms are based on relative lengths of cytogenetic bands.
Consequences of missing data
Either I've been missing something or nothing has been going on. —Karen Elizabeth Gordon
Missing data are everywhere. Subjects may decline to participate in a survey or fail to answer sensitive questions. A cell culture might fail due to contamination. Instrument failures or mishandling of a sample may lead to missing observations. But why are missing data a problem?
This month, we begin a series of articles about practical and statistical aspects of missing data. We'll see that missing data can increase variability and introduce bias and we will ask whether anything can be done to mitigate these consequences. It turns out that, in the case where we know nothing about the missing subjects, no mitigation is possible. We must accept higher variability and, if we have a suspicion that the missing subjects aren’t completely random, possible bias as well.
Tanujit Dey, T., Lipsitz, S.R., Fitzmaurice, G., Krzywinski, M. & Altman, N. (2026) Points of significance: Consequences of missing data. Nat. Methods 23:1661–1663.
Double Robustness
It is not certain that everything is uncertain. —Blaise Pascal
We have already explored how we can mitigate bias caused by confounding variables in observational studies using propensity score (PS) matching (PSM) and propensity score weighting (PSW). However, any statistical model is only as good as its assumptions and, if it is specified incorrectly, it can itself produce biased estimates of the treatment effect.
This month, we explore double robustness, a powerful statistical concept that provides a valuable “safety net” against the risk of an incorrect model. It offers two opportunities, instead of just one, to obtain a valid estimate of the treatment effect — making it possible to draw credible causal inferences from observational data without having to depend on a single set of modeling assumptions.
Kurz, C.F., Krzywinski, M. & Altman, N. (2026) Points of significance: Double Robustness. Nat. Methods 23:868–869.
Nature Biotechnology cover
My cover design on the 7 April 2026 Nature Biotechnology issue shows the dendrogram that represents a cluster of uniquely expressed (or downregulated) genes in human naive stem cells induced from such cells. Within each dendrogram block, the genomic barcode sequence (sampled from Supplementary Table 1) is depicted with a Code 39 barcode. The highlighted barcode is one of those used for cell isolation.
Ishiguro S. et al. A multi-kingdom genetic barcoding system for precise clone isolation (2026) Nature Biotechnology 44:616–629.
Browse my gallery of cover designs.
Happy 2026 π Day—
Art for the 5%
Celebrate π Day (March 14th) and enjoy the art — but only if you're part of the 5%.
Go ahead, see what you can't see.
Ishihara's Tests for Colour Deficiency
Authentic and accurate images of Ishihara's test plates photographed (and lovingly color-corrected) from the 38-plate Ishihara's Tests for Colour Deficiency.
I also provide the position, size, and color of each circle on each test plate.
