Uncategorized on Patrick Stevens

Fun LLM prompt: where are my mental models defective?

Mon, 02 Mar 2026 22:05:00 +0000

A fun prompt to use with a powerful LLM, to learn about something in great detail.

Lessons from a massage course

Sat, 07 Sep 2024 11:47:00 +0100

I went to a one-day intro to massage taster course, and it was fun and interesting!

WoofWare.Myriad.Plugins learns to parse args

Mon, 26 Aug 2024 12:26:00 +0100

My F# source generators have some new features, including an argument parser.

Announcing WoofWare.Myriad.Plugins

Sun, 31 Dec 2023 13:42:00 +0000

Some F# source generators to solve common problems I have.

iOS interface

Sun, 31 Dec 2023 12:49:00 +0000

A bunch of ways the iOS user interface is bad, and some undiscoverable features.

Raymond Smullyan chess problem walkthrough

Fri, 06 Oct 2023 20:53:00 +0100

The thought process behind solving a particular Raymond Smullyan chess retrograde analysis puzzle.

Questions I had about transformers

Wed, 12 Jul 2023 00:00:00 +0000

Some basic questions I had about transformers, and their possible answers.

The water filtration industry has played us for absolute fools

Sun, 15 May 2022 00:00:00 +0000

My Brita water filter does not in fact purify.

Don't supply `-f` to `rm` unless you know you need it

Mon, 25 Oct 2021 00:00:00 +0000

A vignette on the theme of ‘do not allow yourself to get into the habit of supplying the -f flag to rm’.

Argument in a high-trust environment

Thu, 21 Oct 2021 00:00:00 +0000

I tend to argue things in a particular way because I’m in a high-trust environment.

An incomplete life evaluation checklist

Thu, 21 Jan 2021 00:00:00 +0000

A checklist I have used during my regular six-monthly life review.

Christmas quiz

Sat, 26 Dec 2020 00:00:00 +0000

A round of questions I wrote for a Christmas quiz.

Christmas dinner notes

Sat, 21 Nov 2020 00:00:00 +0000

My notes on the production of a Christmas dinner.

Motivational learning

Thu, 29 Jan 2015 00:00:00 +0000

In which I am a wizard.

Sometimes as a student, the work piles up and I start to think “I’ll never finish this”. It becomes easy to think that there’s no point in working because the work will never be over. When that happens to me, I imagine that my course is magic/alchemy/something with flashy special effects. I’m going through the Wizardry Academy, and I’ll graduate able to manipulate the four elements. Even if I’m not the best in the year at it, I’m still able to manipulate the elements, and if I work at it, I’ll be able to manipulate them better and in flashier ways - that’s not something most people can do!

Latin translation tips

Tue, 23 Dec 2014 00:00:00 +0000

I’m clearing out my computer, and found a file which may as well be here.

Chunking:

The first thing to do is to run through the sentence, identifying the verbs and anything that looks like it might be a verb (even in a strange form, like “passus” or “ascendere”).
Run through a second time, looking for structures like “ut + subjunctive” and “non solum… sed etiam…” - if a verb you spotted is in an odd form, this is when you look quickly for why it’s in that form.
Look for any subordinate clauses (like “dixit Caecilius, qui in horto laborabat…”)
If you see an adjective-looking thing, it probably has to go with a noun.
With that in mind, chunk the text, remembering that two verbs in the same chunk is unlikely unless one is something like “dixit” or “poterat”, which can modify another verb. Remember that chunks shouldn’t be too long, but lots of really short words together might not count against the length limit. Try reading out each chunk - rhythm takes time to learn to grasp, but it might help you.

Once the text is chunked:

Remember that your chunking is probably wrong somewhere, but also is probably broadly right.
In each chunk, if there’s a nominative and a verb then try and translate those first. Then think about what the verb “expects”; if the verb is looking for an accusative, find an accusative, while if it’s looking for a dative, find a dative. For example, “docet” = “he teaches” is looking for an accusative, while “trahet” = “he drags” is looking both for an accusative (“he drags something”) and possibly a dative (“he drags something somewhere”).
If it looks like a jumble of words, identify the case of everything (in poetry, it can help if you scan the text) - this should tell you what goes with what. Don’t be too fussy about getting the right case, though - I’d be happy with “dative or ablative”, most of the time, because that’s usually clear from context - as long as you have the right case among your options!

Guessing vocab:

Try and work out what the principal parts of a verb are. The English word from a given Latin one almost always comes from the past passive participle (the fourth principal part), by adding “tion” instead of “us”: “passus” -> “passion” [a bit misleading if you don’t know about the Passion of the Christ, because it means “suffering”], “traho” -> “tractus” -> “traction”; it actually means “drag”. How to guess the principal parts is the kind of thing you learn with time, but as a general rule, “t” -> “s” (as in “patior passus”) and almost everything else goes to “ct”: “pingere pictus” from which “depiction” so “painting”, “facere factus” from which “manufaction” which isn’t really English but tells you it means “making”, etc.

Christmas carols

Tue, 02 Dec 2014 00:00:00 +0000

In which I provide my favourite carols and my favourite renditions of them.

In no particular order, except that 1) must be at the start and 9) at the end.

Once in Royal David’s City. Always opens the Festival of Nine Lessons and Carols. Has the same problem as 9) in that the only nice recordings seem to have congregations in, but I suppose that’s all part of it.
The Three Kings. My favourite. This performance (King’s College) has a soloist who is a bit strident, I think, but all the other ones I’ve listened to are even stridenter.

Perfect pitch

Mon, 21 Jul 2014 00:00:00 +0000

I have a limited form of perfect (absolute) pitch, which I am sometimes asked about. Often it’s the same questions, so here they are. No doubt people with better perfect pitch than mine will be annoyed at this impudent upstart claiming the ability, but perfect pitch comes on a spectrum anyway. Apparently some people can identify notes to within the nearest fifth of a semitone, while some can only identify the semitone closest to the note. I am a bit further towards the “tone-deaf” end of that spectrum.

Music practice

Sat, 19 Jul 2014 00:00:00 +0000

A couple of weeks ago, someone opined to me that there was a type of person who was just able to sit down and play at the piano, without sheet music.

I, myself, am capable of playing precisely one piece inexpertly, from memory, at the piano. (My rendering of that piece is nowhere near the arranger’s standard.) I can play nothing else without sheet music. I very much think that this is the natural state for essentially every musician who has not spent thousands upon thousands of hours practising in a general way. That is, almost no-one can naturally sit down and play a piece from memory without a lot of work beforehand, and almost no-one can improvise well without a great deal of effort directed either at learning how to improvise, or at learning generally the mechanics of playing.

Possible cons of Soylent

Wed, 25 Jun 2014 00:00:00 +0000

I have seen many glowing reviews of Soylent, and many vitriolic naturalistic arguments against it. What I have not really seen is a proper collection of credible reasons why you might not want to try Soylent (that is, reasons which do not boil down to “it’s not natural, therefore Soylent is bad” or “food is great, therefore Soylent is bad”).

This page used to contain citations in the form of links to the Soylent Discourse forum at discourse.soylent.com. However, that site is now defunct.

Useful conformal mappings

Mon, 07 Apr 2014 00:00:00 +0000

This post is to be a list of conformal mappings, so that I can get better at answering questions like “Find a conformal mapping from <this domain> to <this domain>”. The following Mathematica code is rough-and-ready, but it is designed to demonstrate where a given region goes under a given transformation.

whereRegionGoes[f_, pred_, xrange_, yrange_] := 

whereRegionGoes[f, pred, xrange, yrange] = 
 With[{xlist = Join[{x}, xrange], ylist = Join[{y}, yrange]},
 ListPlot[
 Transpose@
 Through[{Re, Im}[
 f /@ (#[[1]] + #[[2]] I & /@ 
 Select[Flatten[Table[{x, y}, xlist, ylist], 1], 
 With[{z = #[[1]] + I #[[2]]}, pred[z]] &])]]]]

Möbius maps - these are of the form \(z \mapsto \dfrac{az+b}{c z+d}\). They keep circles and lines as circles and lines, so they are extremely useful when mapping a disc to a half-plane. A map is defined entirely by how it acts on any three points: there is a unique Möbius map taking any three points to any three points (and hence any circle/line to circle/line). (Some of the following are Möbius maps.)
To take the unit disc to the upper half plane, \(z \mapsto \dfrac{z-i}{i z-1\)}
To take the upper half plane to the unit disc, \(z \mapsto \dfrac{z-i}{z+i}\) (the Cayley transform)
To rotate by 90 degrees about the origin, \(z \mapsto i \)z
To translate by \(a\), \(z \mapsto a+\)z
To scale by factor \(a \in \mathbb{R}\) from the origin, \(z \mapsto a \)z
\(z \mapsto exp(z)\) takes a vertical strip to an annulus - but note that it is not bijective, because its domain is simply connected while its range is not.
\(z \mapsto exp(z)\) takes a horizontal strip, width \(\pi\) centred on \(\mathbb{R}\) onto the right-half-plane.

Maps which might not be conformal

These maps are useful but we can only use them when the domain doesn’t include a point where \(f’(z) = 0\) (as that would stop the map from being conformal).

A roundup of some board games

Thu, 20 Mar 2014 00:00:00 +0000

It has been commented to me that it’s quite hard to find out (on the Internet) what different games involve. For instance, Agricola is a game about farming (and that’s easy to find out), but what you actually do while playing it is not easy to discover. Here, then, is a brief overview of some games.

Agricola

Agricola is a game in which you control a farm, and are aiming to make your farm thrive. It is a multiplayer game (for two to five) divided into turns. During each turn, you can make several actions (the number of actions you can make is determined by the number of people you have on your farm; you start out with two, and some actions increase the number of people you have). The actions are shared between all players - that is, if I make an action, you may not make that same action this turn. There is no other inter-player interaction - no attacking or anything, and you all have your own farm to manage. Your aim is to use actions to gather resources, build and extend your house, and plough fields; at the end of the game (after fourteen rounds, which is about forty minutes) everyone scores their own farm according to a set checklist, and the winner is the one who has the most prosperous farm.

Writing essays

Tue, 28 Jan 2014 00:00:00 +0000

The aim of this post is twofold: to find out whether a certain mental habit of mine is common, and to draw parallels between that habit and the writing of essays.

I don’t know whether this is common or not, but when I’m feeling particularly not-alert (for instance, when I’m nearly asleep, or while I’m doing routine tasks like cooking), I sometimes accidentally latch onto a topic and mentally explain it to myself, as if I were teaching it to the Ancient Greeks (who, naturally, speak English). As an example, last night’s topic of discourse was “the composition of soil”, in which I “talked” about soil, in a manner roughly according to the following diagram. It is laid out so as to display roughly what occurred to me, and the order in which it occurred to me to “say” it.

Denouement of Myst III: Exile

Sun, 12 Jan 2014 00:00:00 +0000

A long time ago, in a galaxy far far away, I completed Myst III: Exile. It’s a stupendously good puzzle game. For some reason, it popped into my mind again a couple of days ago. This post contains very hefty spoilers for that game (it will completely ruin the ending - I will be discussing information-exchange protocols which are key to completing it), so if you’re ever going to play it, don’t read this post yet. It’s a brilliant game - I highly recommend it.

Smartphone Charter

Mon, 30 Dec 2013 00:00:00 +0000

I am shortly to receive a new Nexus 5. I am determined not to become a smartphone zombie, and so I hereby commit to the following Charter.

I will keep my phone free of social networking apps, and I will ensure that I do not know the passwords to access their web interfaces. While they can be really quite handy, they are usually simply a distraction. People are used to the fact that I am present on the Internet only when I have my computer with me; there’s no need for that to change.
I will only look at text messages when I’m not talking to someone already.
I will never look at reddit or Hacker News or suchlike on my phone, unless there is no-one else around. Similarly, I will not access my news feeds from my phone. It’s far too easy to waste time and attention on them, when such attention is expected from the people I’m with.
If I am doing something on my phone, and someone asks me to stop, I will do one of the following (with number 1 being heavily preferred, and number 3 only in emergency):
1. I will stop using my phone within ten seconds
2. I will explain what I am doing, and ask permission to continue
3. I will explain what I am doing (or say that an explanation will be forthcoming as soon as possible), and continue.
I will keep my phone out of reach of my bed when I go to sleep. It’s easy to become lost in the Internet, especially when you’re tired and not really concentrating.
I will be able to access emails on my phone, but I will set it up so that it only checks manually.
I will not install games on my phone. It’s not there as “something to keep me entertained when I’m bored” but as “something to be useful when needed”, and in my experience, games seem to intrude.

If I break any of these, you’re allowed to get annoyed with me. (The converse is false in general.)

The Training Game

Sat, 14 Dec 2013 00:00:00 +0000

The book Don’t Shoot the Dog, by Karen Pryor, contains a simple exercise in demonstrating clicker training. This is a very successful technique used to produce behaviour in animals: having first associated the sound of a click with the reward of attention or food, one can then use the click as an immediate substitute for the reward (so that one can train more complicated, time-critical actions through positive reinforcement; a click is instant, but food or attention requires the trainer approaching the trainee). The demonstration exercise involves a person designated the Trainer, and a person designated the Trainee. The trainer has a goal in mind, but cannot communicate that goal to the trainee; the only interaction allowed is a click when the trainee is doing something vaguely correct. As an example, the trainee can be made to move towards a light switch by dint of a click when ey is pointing towards the switch, then a click when ey moves in that direction (ignoring any attempts to move in a different direction); the trainer then draws attention to the general area of the light by clicking whenever the trainee looks in the right direction, and then for any hand movement, then for hand movement in the direction of the light switch. This kind of incremental reinforcement can be used to achieve all sorts of interesting behaviour. (I seem to remember, from Don’t Shoot the Dog, that it has been used in chickens to make them do hundred-step dances, although I may have mis-remembered that.)

The Jean-Paul Sartre Cookbook

Sat, 23 Nov 2013 00:00:00 +0000

Many thanks to the Guru Bursill-Hall for bringing this tract to my attention through his weekly History of Maths bulletins. It was originally written in 1987 by Marty Smith, according to the Internet.

The Jean-Paul Sartre Cookbook

October 3. Spoke with Camus today about my cookbook. Though he has never actually eaten, he gave me much encouragement. I rushed home immediately to begin work. How excited I am! I have begun my formula for a Denver omelet.

My quest for a new phone

Thu, 07 Nov 2013 00:00:00 +0000

This post is unfinished, and may never be finished - I have decided that the Nexus 5 is sufficiently cheap, nice-looking and future-proof to outweigh the boredom of continuing the research here, especially given that such research by necessity has a very short lifespan. I am one of those people who hates shopping with a fiery passion.

My current phone is a five-year-old Nokia 1680. It has recently developed a disturbing tendency to turn off when I’m not watching it. This puts me in the market for a new phone. Having looked over the Internet for guides to which phone to buy, I’ve become lost in the swamp of information, so I am using this post to order my thoughts.

Meaning what you say

Fri, 11 Oct 2013 00:00:00 +0000

In conversation with (say, for the purposes of propagating a sterotype) humanities students, I am often struck by how imprecisely language is used, and how much confusion arises therefrom. A case in point:

A: I think that froogles should be sprogged!

B: Sprogging froogles would make the bimmers go plog.

A: But I use froogles all the time - I don’t care about the bimmers! Why are you so caught up on the plogging of bimmers?

How to prove that you are a god

Sat, 21 Sep 2013 00:00:00 +0000

I came across an interesting question while reading the blog of Scott Aaronson today. The question was as follows:

In the world of the colour-blind, how could I prove that I could see colour?

I’m presuming, to make the discussion more life-like and less cheaty, that this civilisation hasn’t discovered that light comes in wavelengths, or that it has but it can’t distinguish very well between wavelengths (so that all coloured light falls into the same bucket of 100nm to 1000nm, for instance). The challenge is to design an experimental protocol to confirm or deny that I have access to information that the colour-blind do not. This question is much harder than the corresponding question in the world of the blind, because having vision tells you so much more than having colour vision (simply set up a flag two miles away, have someone raise it at a random time, note down the time you saw it raised, and compare notes).

How to punt in Cambridge

Thu, 22 Aug 2013 00:00:00 +0000

When in Cambridge…

The river is always full of beginners and professional puntists. The beginners veer all over the place, getting very wet, while the professionals zip between them, somehow managing to avoid collision by the width of an otter’s hair. The worst attempt by a beginner I’ve ever seen at punting was an attempt to use the pole rather like an oar, without ever touching the bottom of the river with it. This patent perplexity pertaining to the point of the punt provoked a pertinent post.

New computer setup

Sun, 04 Aug 2013 00:00:00 +0000

Editor’s note: this is a snapshot of life in 2013-08-04. My setup has changed substantially since then.

In case I ever have to get a new computer (or, indeed, in case anyone else is interested), I hereby present the (updating) list of applications and so forth that I would immediately install to get a computer up to usability.

Browser: Firefox with Ghostery, HTTPS Everywhere, and NoScript (and remember to turn on Do Not Track…)
Mail client: Thunderbird with Enigmail
Messaging client: Adium on Mac, and possibly Pidgin for others - I’ve never used a non-Mac chat client. Beware: as of this writing, Pidgin stores passwords in plain text, so don’t save passwords in Pidgin.
Encryption: GPG (Windows, Mac, Linux)
Text editor: Vim
Memory training: Anki
Movie viewing: VLC
Screen colour muter: f.lux
Backup software: CrashPlan - but I also keep local backups using whatever built-in automated backup utility the OS provides
FTP client: FileZilla, or Cyberduck on a Mac
Syncing: Dropbox (but I want to get rid of this, because of privacy concerns)
Computational software: Mathematica
Music: iTunes (but I want to switch this for something not-Apple, and it has no Linux version)
Gaming: Steam
RSS reader: Currently, my RSS feed is presented in-browser, at NewsBlur.

On to-do lists as direction in life

Tue, 30 Jul 2013 00:00:00 +0000

Getting Things Done has gathered something of a cult following [archived due to link rot] since its inception. As a way of getting things done, it’s pretty good - separate tasks out into small bits on your to-do list so that you have mental room free to consider the bigger picture. However, there’s a certain aspect of to-do lists that I’ve not really seen mentioned before, and which I find to be really helpful.

On Shakespeare

Sun, 21 Jul 2013 00:00:00 +0000

I’ve now seen two Shakespeare plays at the Globe - once in person, to see A Midsummer Night’s Dream, and once with a one-year-and-eighty-mile gap between viewing and performance (through the Globe On Screen project), to see Twelfth Night. Both times the plays were excellent. Both were comedies, and both were laugh-out-loud funny.

The performance of Twelfth Night, then, was beamed into a local-ish cinema for our viewing pleasure. (Definitely more comfortable than the seating at the Globe, although I am reliably informed that if you go to the Globe, you really have to be a groundling, standing at the front next to the stage, in order to get the proper experience.) My seat was next to those of some young-ish children. The result of taking several young children to a three-hour performance of a play which isn’t in Modern English was predictable, but it got me thinking. (Bear with me - this will become relevant.)

Imre Leader Appreciation Society

Wed, 10 Jul 2013 00:00:00 +0000

There was once a small website devoted to noting the more interesting quotes from our more idiosyncratic lecturers. It sadly vanished from the web, although after some detective work, I found a copy floating around on one of Amazon’s servers. I stored them for posterity using the archival service WebCitation, which is itself now dead, so instead I shall link to Konrad Dąbrowski’s capture.

An obvious improvement to tennis

Mon, 08 Jul 2013 00:00:00 +0000

So yesterday the Wimbledon tennis tournament was decided. The system for verifying whether the tennis ball is out or not (and hence whether play for the point stops or continues) on the main courts is as follows:

The ball lands.
The linesperson keeping charge of the line nearest to the landing point of the ball works out whether the ball landed inside or outside the region demarcated by the line.
The umpire decides whether or not to overrule the linesperson’s decision.
The Hawkeye ball-tracking system determines whether the ball landed inside or outside the region demarcated by the line.
If either player disagrees with the official decision (that is, if the linesperson called “out” when the player thought the ball was in, or the linesperson was silent when the player thought the ball was out, or if the umpire overruled a decision that the player thinks was correct) then that player informs the umpire that ey wishes to “challenge” the linesperson. In this instance, the Hawkeye reading is consulted (and the ball’s trajectory slowly animated on a big screen, for added tension) and regarded as definitive.

The problem I have with this system is the process of “challenging”. Each player starts out with a challenge count of three. If a player makes a challenge, and Hawkeye contradicts the official call, then the challenge count is maintained at its current level. If a player makes a challenge, and Hawkeye agrees with the official call, then the challenge count for that player is decremented. A player cannot challenge if eir challenge count is 0. On entering a tie-break, each player’s challenge count is incremented.

Cambridge vocab - a guide for the mystified

Sat, 06 Jul 2013 00:00:00 +0000

There is an awfully large collection of confusing words you will encounter on first coming to study at Cambridge. You pick them up really quickly in the natural run of things, but I thought perhaps a mini-dictionary might be helpful. The list is alphabetised (if I’m competent enough, anyway) and may, like so many of my writings, grow. Apologies for my crude attempts at pronunciations for the non-obvious words, but it’s very hard to find someone who can read IPA.

Cambridge undergrad maths tips

Thu, 04 Jul 2013 00:00:00 +0000

I wrote this when I was excessively bored during exam term of my first year. It may grow as I get better at working (I’m something of a revisionist). The advice is entirely Cambridge-based; a lot of it probably applies to other places with minor alterations. Most of this comes from personal experience.

During a supervision, your supervisor will be writing all the time. As soon as you leave the supervision, mark the sheets that are particularly important in some obvious way (eg. by colouring in the corner). That way, when you’re frantically flicking through the notes at the end of the year, you’ll see where the information you need is. By “most important”, I mean the places where the supervisor explains something fundamental to many questions, rather than the ins and outs of one particular question.

In which I augment the lexicon

Wed, 03 Jul 2013 00:00:00 +0000

A few dubiously-real words which I think should be more widely used.

CUCaTS Puzzlehunt

Wed, 26 Jun 2013 00:00:00 +0000

At the end of last (that is, Lent 2012-2013) term at Cambridge, I took part in the Cambridge University Computing and Technology Society Puzzlehunt (for some reason, as of this writing, they haven’t yet updated that page for this year’s Puzzlehunt, but last year’s is up there). A short summary: the Puzzlehunt is a treasure hunt around Cambridge, crossed with a whole bunch of online computing-based puzzles. It’s very difficult, and it lasts for twenty-four hours.

First post

Wed, 26 Jun 2013 00:00:00 +0000

Hello all!

In the spirit of shouting into an echoing void, this is my first post, testing whether the setup works. Some content will probably turn up soon.