Programming languages such as Python and Rust are often developed in the open on GitHub and have histories that may extend decades into the past. For those curious to discover patterns hiding in the depths of time, the tree ring charts below illustrate the commit histories for some popular open-source languages.

Python is a general-purpose programming language.

Each chart is made up of a single spiral traveling around and around at one revolution per year.

The thickness of the line shows the number of commits each day — thicker lines mean more commit activity.

Yellow circles highlight significant releases (in this case, Pythons 1, 2, and 3). The big red circle is the single most active day.

Ruby is another general-purpose programming language.

Here's the same chart for Ruby. You can see the straight line of Christmas releases since 2013, and the increase in development in the months preceding it.

Another language well known for its Christmas release is Perl 6, delivered Christmas 2015 after an almost sixteen-year gestation (the chart, tracking only GitHub history, illustrates the journey from 2006).

Corporate Languages

The languages discussed so far have all had their roots in purely open development. How do things look for languages developed by companies?

Swift and Go are both corporately led, and it shows — observe, for example, the near-total cessation of activity around Christmas Day.

Kotlin is a general-purpose language for Android.

V8 is the JavaScript engine underlying Chrome.

JetBrain's Kotlin and Google's Javascript engine also show this pattern. The galactic look is due to the workweek cycle; the clumps are weekdays, with weekends interleaved.

Appendix: Other Programming Languages