buy artwork
Pi Day 2023 — Repeated Sequence — A modular synthesizer experience
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.
People find these numbers inconceivable — and I do too. Best thing to do is just relax and enjoy it. —Richard Feynman
Welcome to 2023 Pi Day: a celebration of `\pi` and mathematics, electronic music and cables. A lot of cables.
The series of images below walk you through the essentce of modular synthesis. The graphic is a simplification — I have left out details at each step and there are many more types of modules. Even within a family of modules (e.g., oscillator) there is a large variety (e.g. waveform, FM synthesis, etc).
Greg's notes
After our successful collaboration on the collection of piano pieces written to celebrate Pi Day 2022, Martin asked me to be involved in creating his vision for Pi Day 2023. I was excited to say yes.
I have been exploring Eurorack modular synths for some years now, and had introduced Martin to the sounds and capabilities of these remarkable machines. Martin took them like a duck to water, and in a matter of weeks, had ordered a case to be built, and was buying modules like they were going out of fashion.
My role in the project this year was to contribute technical advice, and to guide the building of the musical structure on which the piece was based. I decided that a key component of the piece would be a well defined harmonic progression.
I chose to use the Moog Matriarch as it is semi-modular — it can interface with modular synths via internal patch points. The Matriarch provides a subtle, ever-changing harmonic structure that roots the piece. It is sequenced internally via the Matriarch's sequencer, and in the middle section of the piece, the internal clock is modulated via the slowest Inertia output from the Nonlinear Circuits Triple Sloth, as is the onboard delay.
The harmonic language was derived from the piece Down Here/Moon Above, by Flunk. My role also involved manipulating banks of samples in several sampling modules - namely the Instruō Lúbadh, the 4ms STS Sampler and the Make Noise Morphagene.
As a final stage, I mastered the audio using Izotope Ozone.
Symmetric alternatives to the ordinary least squares regression
What immortal hand or eye, could frame thy fearful symmetry? — William Blake, "The Tyger"
This month, we look at symmetric regression, which, unlike simple linear regression, it is reversible — remaining unaltered when the variables are swapped.
Simple linear regression can summarize the linear relationship between two variables `X` and `Y` — for example, when `Y` is considered the response (dependent) and `X` the predictor (independent) variable.
However, there are times when we are not interested (or able) to distinguish between dependent and independent variables — either because they have the same importance or the same role. This is where symmetric regression can help.
Luca Greco, George Luta, Martin Krzywinski & Naomi Altman (2025) Points of significance: Symmetric alternatives to the ordinary least squares regression. Nat. Methods 22:1610–1612.
Beyond Belief Campaign BRCA Art
Fuelled by philanthropy, findings into the workings of BRCA1 and BRCA2 genes have led to groundbreaking research and lifesaving innovations to care for families facing cancer.
This set of 100 one-of-a-kind prints explore the structure of these genes. Each artwork is unique — if you put them all together, you get the full sequence of the BRCA1 and BRCA2 proteins.
Propensity score weighting
The needs of the many outweigh the needs of the few. —Mr. Spock (Star Trek II)
This month, we explore a related and powerful technique to address bias: propensity score weighting (PSW), which applies weights to each subject instead of matching (or discarding) them.
Kurz, C.F., Krzywinski, M. & Altman, N. (2025) Points of significance: Propensity score weighting. Nat. Methods 22:638–640.
Happy 2025 π Day—
TTCAGT: a sequence of digits
Celebrate π Day (March 14th) and sequence digits like its 1999. Let's call some peaks.
Crafting 10 Years of Statistics Explanations: Points of Significance
I don’t have good luck in the match points. —Rafael Nadal, Spanish tennis player
Points of Significance is an ongoing series of short articles about statistics in Nature Methods that started in 2013. Its aim is to provide clear explanations of essential concepts in statistics for a nonspecialist audience. The articles favor heuristic explanations and make extensive use of simulated examples and graphical explanations, while maintaining mathematical rigor.
Topics range from basic, but often misunderstood, such as uncertainty and P-values, to relatively advanced, but often neglected, such as the error-in-variables problem and the curse of dimensionality. More recent articles have focused on timely topics such as modeling of epidemics, machine learning, and neural networks.
In this article, we discuss the evolution of topics and details behind some of the story arcs, our approach to crafting statistical explanations and narratives, and our use of figures and numerical simulations as props for building understanding.
Altman, N. & Krzywinski, M. (2025) Crafting 10 Years of Statistics Explanations: Points of Significance. Annual Review of Statistics and Its Application 12:69–87.
Propensity score matching
I don’t have good luck in the match points. —Rafael Nadal, Spanish tennis player
In many experimental designs, we need to keep in mind the possibility of confounding variables, which may give rise to bias in the estimate of the treatment effect.
If the control and experimental groups aren't matched (or, roughly, similar enough), this bias can arise.
Sometimes this can be dealt with by randomizing, which on average can balance this effect out. When randomization is not possible, propensity score matching is an excellent strategy to match control and experimental groups.
Kurz, C.F., Krzywinski, M. & Altman, N. (2024) Points of significance: Propensity score matching. Nat. Methods 21:1770–1772.