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# pi: beautiful

More than Pretty Pictures—Aesthetics of Data Representation, Denmark, April 13–16, 2015

# visualization + design

Typography geek? If you like the geometry and mathematics of these posters, you may enjoy something more lettered. Visions of type: Type Peep Show: The Private Curves of Letters posters.

# Pi Day Art Posters — March 14, 2014

All posters are available for purchase.
I also take custom requests.

Two styles of posters are available: folded paths, which show Pi on a path that maximizes adjacent prime digits, and frequency circles, which colourfully depicts the ratio of digits in groupings of 3 or 6.

Pi Day 2014 path posters (view posters, BUY ARTWORK)
Pi Day 2014 frequency circles posters (view posters, BUY ARTWORK)

## posters — folded paths

Pi Day 2014 poster | 132 paths with E=-23 of 64 digits of Pi, sorted by aspect ratio. Start (3) and end (2) digits are highlighted. (zoom, BUY ARTWORK)

Pi Day 2014 poster | 132 paths with E=-23 of 64 digits of Pi, sorted by aspect ratio. Start (3) and end (2) digits are highlighted. (zoom, BUY ARTWORK)

Pi Day 2014 poster | 132 paths with E=-23 of 64 digits of Pi, sorted by aspect ratio. Prime (2 3 5 7) digits are are highlighted. (zoom, BUY ARTWORK)

Pi Day 2014 poster | 132 paths with E=-23 of 64 digits of Pi, sorted by aspect ratio. Digits are colored by prime/composite status. (zoom, BUY ARTWORK)

Pi Day 2014 poster | 9 paths with E=-223 to -220 of 768 digits of Pi, sorted by aspect ratio. Start (3) and end (999999) digits are highlighted. (zoom, BUY ARTWORK)

Pi Day 2014 poster | 9 paths with E=-223 to -220 of 768 digits of Pi, sorted by aspect ratio.. Start (3) and end (999999) digits are highlighted. (zoom, BUY ARTWORK)

Pi Day 2014 poster | 9 paths with E=-223 to -220 of 768 digits of Pi, sorted by aspect ratio.. Prime (2 3 5 7) digits are are highlighted. (zoom, BUY ARTWORK)

Pi Day 2014 poster | 9 paths with E=-223 to -220 of 768 digits of Pi, sorted by aspect ratio. Digits are colored by prime/composite status. (zoom, BUY ARTWORK)

Pi Day 2014 poster | 20 paths with E=-223 to -209 of 768 digits of Pi, sorted by distance between start and end points (2.2–7.0). Start (3) and end (999999) digits are highlighted. (zoom)

Pi Day 2014 poster | The lowest energy path E=-223 of 768 digits of Pi. Start (3) and end (999999) digits are highlighted, as well as all prime digits. This path took about 1 CPU year to find. (37x51, r=0.725, area=1887, cm=1.9/13.4, dend=24.4) (zoom)

# Split Plot Design

Tue 03-03-2015

The split plot design originated in agriculture, where applying some factors on a small scale is more difficult than others. For example, it's harder to cost-effectively irrigate a small piece of land than a large one. These differences are also present in biological experiments. For example, temperature and housing conditions are easier to vary for groups of animals than for individuals.

Nature Methods Points of Significance column: Split plot design. (read)

The split plot design is an expansion on the concept of blocking—all split plot designs include at least one randomized complete block design. The split plot design is also useful for cases where one wants to increase the sensitivity in one factor (sub-plot) more than another (whole plot).

Altman, N. & Krzywinski, M. (2015) Points of Significance: Split Plot Design Nature Methods 12:165-166.

1. Krzywinski, M. & Altman, N. (2014) Points of Significance: Designing Comparative Experiments Nature Methods 11:597-598.

2. Krzywinski, M. & Altman, N. (2014) Points of Significance: Analysis of variance (ANOVA) and blocking Nature Methods 11:699-700.

3. Blainey, P., Krzywinski, M. & Altman, N. (2014) Points of Significance: Replication Nature Methods 11:879-880.

# Color palettes for color blindness

Tue 03-03-2015

In an audience of 8 men and 8 women, chances are 50% that at least one has some degree of color blindness1. When encoding information or designing content, use colors that is color-blind safe.

A 12-color palette safe for color blindness

# Points of Significance Column Now Open Access

Tue 10-02-2015

Nature Methods has announced the launch of a new statistics collection for biologists.

Nature Methods Points of Significance column is now open access. (column archive)

As part of that collection, announced that the entire Points of Significance collection is now open access.

This is great news for educators—the column can now be freely distributed in classrooms.

# Before and After—Designing Tiny Figures for Nature Methods

Tue 13-01-2015

I've posted a writeup about the design and redesign process behind the figures in our Nature Methods Points of Significance column.

I have selected several figures from our past columns and show how they evolved from their draft to published versions.

Fig 2 from Points of Significance: Nested designs. (Krzywinski, M. & Altman, N. (2014) Nature Methods 11:977-978.) (...more)

Clarity, concision and space constraints—we have only 3.4" of horizontal space— all have to be balanced for a figure to be effective.

Fig 2c (excerpt) from Points of Significance: Designing comparative experiments. (Krzywinski, M. & Altman, N. (2014) Nature Methods 11:597-598.) (...more)

It's nearly impossible to find case studies of scientific articles (or figures) through the editing and review process. Nobody wants to show their drafts. With this writeup I hope to add to this space and encourage others to reveal their process. Students love this. See whether you agree with my decisions!

# Sources of Variation

Thu 08-01-2015

Past columns have described experimental designs that mitigate the effect of variation: random assignment, blocking and replication.

The goal of these designs is to observe a reproducible effect that can be due only to the treatment, avoiding confounding and bias. Simultaneously, to sample enough variability to estimate how much we expect the effect to differ if the measurements are repeated with similar but not identical samples (replicates).

Nature Methods Points of Significance column: Sources of Variation. (read)

We need to distinguish between sources of variation that are nuisance factors in our goal to measure mean biological effects from those that are required to assess how much effects vary in the population.

Altman, N. & Krzywinski, M. (2014) Points of Significance: Two Factor Designs Nature Methods 11:5-6.

1. Krzywinski, M. & Altman, N. (2014) Points of Significance: Designing Comparative Experiments Nature Methods 11:597-598.

2. Krzywinski, M. & Altman, N. (2014) Points of Significance: Analysis of variance (ANOVA) and blocking Nature Methods 11:699-700.

3. Blainey, P., Krzywinski, M. & Altman, N. (2014) Points of Significance: Replication Nature Methods 11:879-880.

# Two Factor Designs

Tue 09-12-2014

We've previously written about how to analyze the impact of one variable in our ANOVA column. Complex biological systems are rarely so obliging—multiple experimental factors interact and producing effects.

ANOVA is a natural way to analyze multiple factors. It can incorporate the possibility that the factors interact—the effect of one factor depends on the level of another factor. For example, the potency of a drug may depend on the subject's diet.

Nature Methods Points of Significance column: Two Factor Designs. (read)

We can increase the power of the analysis by allowing for interaction, as well as by blocking.

Krzywinski, M., Altman, (2014) Points of Significance: Two Factor Designs Nature Methods 11:1187-1188.