Linkage

Competitive Programmer’s Handbook. Although it is aimed at participants in programming competitions this new free-online book has most of the same content as an undergraduate algorithms text.

Owen Schuh’s mathematical art includes “Disturbance”, an interlocked set of white arcs on a black field that look much like a Mark Lombardi drawing.

Harry R. Lewis gets a Wikipedia Good Article about him for his 70th birthday.

Scott Aaronson rants about calendars and time zones. The default time zone needs to be “wherever I will be when this event happens”, not “where I was when I put this on my calendar”.

Paint commercial (G+) with beautiful slow-mo footage of paint streams interacting in water, and no CGI.

The strip pentiamond joins the ranks of the reptiles, in answer to a question on MathOverflow.

A New Path to Equal-Angle Lines. Quanta reports on a preprint of Balla et al showing that for any fixed angle \(\theta\), in high enough dimensions, at most a linear number of lines through the origin can all form angles of \(\theta\) with each other. See also an earlier paper showing that if \(\theta\) can vary with dimension then quadratically many equiangular lines are possible.

A reversible cellular automaton that supports vibrating strings (G+). Via Tim Hutton, who posted a nice gif of the automaton in action.

Chronophotographs of birds in flight by Xavi Bou, showing the time-lapse shapes made by their motion.

Plagiarists are now using automatic paraphrasing software to evade detection. Do we need to fight fire with fire by using parameterized string matching algorithms?

A lizard whose scale patterns are generated by a long-term cellular automaton. The original research paper was just published in Nature.

Turkey blocks Wikipedia (G+), apparently because Wikipedia refuses to prevent non-Erdogan-supporters from editing.