Economics

• Markets are efficient if and only if P = NP

  Most economists believe that markets are efficient, most computer scientists believe that P != NP. If this paper is correct, the consensus in one of these fields is very wrong.

Programming

• Trygve Reenskaug - DCI: Re-thinking the foundations of object orientation and of programming

  A long-term view of programming, from someone who was there at the beginning. Programming in the 50s and 60s was lean and agile, and procedural code was easier to read and verify than Object Oriented code. Shame about the dude that starts a Scrum pitch about 35 minutes in - keep watching, he goes away. For a light written overview of Reenskaug's argument, see here, and for a more concrete example of the Data Collaborations and Interactions architecture, see here.

• Twitter using BitTorrent on the Backend

  Using BitTorrent to roll out data to a server flock. Nice idea, nice implementation.

• Gallery of Processor Cache Effects

Maths

• Gruenberger's prime path

  Musings on a geometric path that can be traced using prime numbers, with accompanying visualisations.

• World's Hardest Easy Geometry Problem

  I had fun working on a printout of this problem over my morning coffee at a local cafe. Yes, it can be solved using only elementary geometry.

Social media

• onesocialweb - free open decentralized networking platform

  Built on top of XMPP. My gut feeling is that something simpler is called for.

Visualisation

• Analysis of a Harmonograph I Built

  A meatspace visualisation of dampened harmonic motion using a ladder, 45kg of weights and a pen.

• A celebration of color

  Some nice image colour decomposition, somewhat similar to a recent blog post I did that uses the Hilbert curve to do decompositions.

• Modelling lightning in Haskell

  A neat idea, touching on some interesting algorithms along the way. Pity the full source isn't published.

Astrobiology

And now for something completely different.

• Spectral signatures of photosynthesis: coevolution with other stars and the atmosphere on extrasolar worlds (pdf)

  After journeying for millennia through cold, unforgiving interstellar space, a small group of human astronauts finally reach a world harbouring life. As the landing craft approaches the surface of the planet, our intrepid voyagers are astonished to find themselves descending through the lush canopy of an alien forest, teeming with creatures beyond imagination. Now... what colour are the leaves? This paper is a first step towards guessing at a question I've been dreaming about since childhood. See also the companion paper reviewing photosynthetic pigments on earth.