Physicists seem still to be taught about tensors as being, essentially, multidimensional arrays with special transformation rules which must be learned by rote. So I wrote a document which tries to present a more useful approach.

Do not eat the free lunch: it has probably been poisoned.

I play the guitar. Something that has been fashionable for some time is what are often called ‘road worn’ guitars. In other words new (but vintage-spec) guitars which have been aggressed in various ways to make them look old.

How easy are physical systems to predict?

When I first used Lisp, the common refrain was that Lisp was dead.

The second part of my notes on writing macros in Racket.

People often ask which Pentax film SLR to get. In brief: get an MX with a 50/1.4.

I’ve written in Lisp for a long time, but I’ve never used a hygienic macro system in any way other than the most simple. Here are some initial notes on my experiences learning Racket’s macro system.

Programming is not meant to be easy and it’s important to make sure that it is as cryptic as possible otherwise people other than cult members might be able to understand it. Of course, you also need to make sure it’s pure, because otherwise cult members will laughingly throw you into a pit full of spikes and the rotting remains of other heretics.

Investment bankers are often called ‘sharks’ and this is, in fact, a good description. There is nothing wrong with sharks: they are beautiful animals designed by billions of years of natural selection to do one thing extremely well. You can not expect a shark to be other than a shark: rather you must understand how sharks behave and arrange matters so as not to be eaten. Governments can do this for banks: they did it in 1933, after all, and it served us well for nearly 70 years. However governments entirely failed to do this after the events of 2008 for reasons of stupidity and corruption.