part of the “what I learned after four years at MIT” series, I guess?
I hated timed essays in high school. It’s pretty clear if you skim that part of the blog archives:
My [SAT] essay got a 10 out of 12. It’s an essay I’d be ashamed of posting anywhere else; it’s disgustingly traditional and formulaic. […] This was simply because I knew that using my normal essay-writing mindset, I’d get maybe a 3, because I’d spend the first twenty minutes debating myself over which side I was on and rewrite the introduction ten times. Too bad. I wasn’t there to write a good essay; I was there to get a good score on the SAT.
The worst issue is that students do not need to give in-depth explanation of anything they learned. Due to its stringent time limit, the essay portion rewards quick reckless writing much more than deep thought. […] encouraging students to practice writing 25-minute essays in order to improve their college-bound skills is like encouraging people to play Grand Theft Auto in order to improve their driving skills.
I took the Grand Theft Auto analogy pretty far. I’m not proud enough of these posts to link them, but you can find them if you try. In short, past me thought timed essays rewarded writing too quickly, with a disregard not only for facts but for the opportunity to lay out your opinions and thoughts so you could clarify and revise them, which was actually the most valuable part of writing.1 I conceded that the time limits made sense as a practical concession to allow you to test students’ writing skills fairly,2 but I felt like there was still way too much emphasis on the raw speed.
Part of a series of posts about what I learned after four years at MIT. We’re ramping up to deeper topics eventually, I promise. Soon™.
This post is about things. You know, physical objects. Earthly possessions. The indispensable yet fickle chains that bind us to this plane of existence.
As a freshman I loved getting free stuff. I went into my first career fair starry-eyed, taking free pens and t-shirts and sunglasses and drawstring bags from every company that would let me; I’m sure many other MIT students have gone through the same ritual of passing. There seemed to be no downside. Besides, all the swag was probably small change for most of the companies anyway, due to VC funding or massive government contracts or whatever. So I might as well make full use of it.
Less normally (although I have no idea by how much), I also hoarded a lot of things that naturally pop up in everyday life, the stuff that would otherwise get thrown away: extra napkins, plastic bags, produce containers, boxes, those payment envelopes that come with magazine subscriptions and exhort you to Subscribe Now To 12 Issues For 20% Off!! At some point I kept the fortune from every fortune cookie I had ever eaten in a tiny resealable bag. The rationale was basically the same: they might be useful some day1 and there was no downside.
I wanted to write a post after two years at college about everything I had learned. I didn’t, firstly because I didn’t make it a priority, and secondly because trying to write about everything I’ve learned at MIT over any nontrivial length of time is the kind of poorly scoped endeavor that I could never complete to my own satisfaction.
Two years came and went, and now it’s been two more years and I’ve learned even more things, not to mention, actually graduated. Jeez. I tried to self-impose a deadline for the big post, but it didn’t work out. There were still too many higher priorities, most of which were also natural consequences of graduating. I also couldn’t bring myself to cut anything, because unlike most of the stuff I haphazardly throw onto this blog, I can actually imagine an audience for just about everything I wanted to write about.
Finally I decided that I would break it into lots of small posts on specific topics. This way, at least the perfectionism can’t bleed between posts too much. The first topic I wanted to write about is simple, mundane, and also fairly limited in scope itself: how to choose your MIT username.
In this challenge, we get a gzipped file called perf.data and a minimal description of an environment. Googling this reveals that perf.data is a record format of the perf tool, a Linux profiler. Installing perf allows us to read perf.data and see some pretty interactive tables of statistics in our terminal describing the profiling results, from which we can see some libraries and addresses being called, but they don’t reveal much about what’s going on. One hacky way to see more of the underlying data in a more human-readable way (and to see just how much of it there is) is perf report -D, which dumps the raw data in an ASCII format, but this is still not that useful. (One might hope that one could simply grep for the flag in this big text dump, but it’s nowhere to be seen.) Still, from this file, we can definitely read off all the exact library versions that the perf record was run against.
I put this question in my FAQ, because at least two people have asked me this question, and that’s how frequent a question needs to be to be on my FAQ: I got an IMO1 gold medal in 2012, as a ninth grader, and an IOI gold medal in 2014, as an eleventh grader. I could have kept going to either, or even decided to try taking the IPhO or something, but I didn’t. Why not?
The short answer: It was a rough utilitarian calculation. By continuing, I would probably displace somebody else who would gain more from being on an IMO/IOI team than I would. Besides, I wanted to do other things in high school, so I wasn’t losing much.
I think the short answer actually captures most of my thinking when I made the decision back then, and it’s not really new; I said as much at the end of 2013. But behind it was a lot of complex thoughts and feelings that I’ve been ruminating over and trying to put into words for the better part of a decade. Hence, this post.
There is a natural question that precedes the frequently asked one that I have never been asked, something I am now realizing I never honestly asked myself and never tried to answer deeply: Why did I participate in the IMO and the IOI in the first place?
(this post is sketchily backdated from February 2020)
Fourth year with ✈✈✈ Galactic Trendsetters ✈✈✈. Past: 2018, 2017, 2016, writing with Random in 2015). Evidently I was unable to find the time or motivation to blog about this, and I can’t remember any particularly good stories, so let me just slip this backdated list post in the archives.
The theme in a few sentences: The hunt organizers declare a new Molasses Awareness Day, but because they didn’t follow the proper procedure, throwing the world of Holidays into chaos, where “chaos” means molasses. This resulted in lots of puzzle-to-meta matching, since puzzles were in Holiday towns but metas were at lampposts between two towns.
Highlights of puzzles I solved:
A Good Walk Spoiled (Holi): Happens to be about a topic I know well and find interesting. Fun steps. Justified use of substitution ciphers; the pasting into quipqiup was worth it.
State Machine (President’s): A one-aha! one-step puzzle. Maybe more unfortunate because apparently this was not the only puzzle to use a specific aspect of a specific source material, but I didn’t know about that other puzzle so it’s fine.
Clued Connections (Pi): I went to sleep near the end of this puzzle, so I didn’t see it through, but Floorpi was collectively called out by it.
I Can’t Deal with These Endless Numbers (Patriot’s): Incredible.
I was pretty torn between this and “The Future Soon” as the Year-End Song on this blog, but in the end I think I feel more threatened by the bland existence of the soulless adult than inspired by the starry-eyed-idealism-with-misogynist-undertones of the twelve-year-old, plus I get to show you the best kinetic typography video I have ever seen.
Halfway through 2018 I thought this would be the year of ephemeral phases. I felt like I went through a different phase every month — Online Dominion in April, crosswords in June, Only Connect in July, Jonathan Coulton in August, a brief stint of trying really hard to barre my guitar chords in October. Somewhere in the middle, I discovered Kittens Game (“the Dark Souls of Incremental Gaming”) and my summer internship mentor got me to pick up Pokémon Go again. A few intense periods of typographical study were interspersed, which involved watching the above music video dozens of times, teaching a Splash class on typography, and developing a new awareness of how Avenir was everywhere. During the last month, I went hard on Advent of Code and got second place, apparently the only person to make it on every single leaderboard. I also did a related golf side contest and poured a couple more hours into Paradoc, my personal golfing language, for rather unclear gain. At least I got a lot of GitHub followers?
It would turn out, though, that a lot of these phases had more staying power than I expected. Pokémon Go is a much better game than it was two years ago and has actually fostered a significant real-life community, which seems like one of the best possible outcomes of an augmented reality game, and I’ve found a steady pace to play at. I spread the Only Connect bug and people on my hall, intrigued by the format but annoyed by the overwhelmingly British trivia1, started writing and hosting full games for each other, with our own MIT-slanted set of trivia. One of us developed a custom site and tool to host these games. It took me a while to warm up to Jonathan Coulton’s latest album, but since it happened, I cannot get Ordinary Man or Sunshine out of my head; I’m still listening to JoCo as I finish typing up this post. Although I never got back to the peak of my crossword frenzy, I still study crosswordese from time to time and compose crosswords for some special occasions, like this one (.puz file).
The academics and technical aspects of this year have all blurred together, but I think my interests are finally crystallizing:
A more accurate but less informative title for this post would be “How I wish React and Redux were explained to me”. Note that this does not imply that this method of explanation is suitable for anybody else. I suspect it won’t be for most people.
I had to learn React and Redux the past summer for my internship at MemSQL, and there were hundreds of articles that explain React and Redux in addition to the (fine) built-in documentation, but none of them scratched the itch; I wanted to know what was going on completely, including some of the technical details and the philosophy I ought to be following, as well as efficiently. I did not need another explanation about how to think functionally, in JavaScript types or with immutable data. React’s chapter on Conditional Rendering, for example, felt so inefficient — I know what if statements and conditional expressions are, and I know how to refactor complicated subexpressions into variables…
So here’s the guide I wish I had. I think. It’s been months since I started it (as usual, for posts on this blog) and it is probably incomplete. However, I haven’t written React/Redux deeply in a while, so I didn’t have much motivation to continue to investigate the incomplete bits; and the perfect is the enemy of the good, so here it is.
We’ve burrowed ourselves deep within the facility, gaining access to the programable logic controllers (PLC) that drive their nuclear enrichment centrifuges. Kinetic damage is necessary, we need you to neutralize these machines.
A much belated post. This is a pwn challenge on a custom online wargaming platform. We are provided with the assembly of what’s ostensibly a programmable logic controller (PLC) for a centrifuge in a nuclear reactor. The challenge looks like it’s still up, so you can take a look and follow along.
This was the first ROP (okay, spoiler, it’s a ROP) I ever pulled off live during an actual CTF, which I was pretty excited about. The web platform meant I had to worry less about setup, and even though some of the tools it provided were a little lacking (no gdb shortcuts like until, no pwntools utilities for packing/unpacking numbers, … no one_gadget), I think they ultimately made the whole thing a lot more educational for me, so kudos to the folks behind it. I’ve included a brief description of all the exploit techniques that lead up to ROP when we get to that, so hopefully this post will be useful even if you don’t know much about pwning binaries. The prerequisites would be some knowledge with x86 assembly, how executables are loaded into memory, and how to use gdb (or fictionalized web knockoffs thereof).
The villains are communicating with their own proprietary file format. Figure out what it is.
$ nc proprietary.ctfcompetition.com 1337
We get a server that will talk to us on a port and a flag.ctf file that’s definitely not a binary. It’s a black-box reversing challenge! I was @-mentioned as the person who might want to due to solving bananaScript (CSAW CTF Quals 2017) as a black box, although that gave a binary that it was possible in theory to reverse. Here black-box reversing is the only option.
For the first few lines of input that the server wants, it responds with quite helpful error messages to help you appease it. If the first line you give it is not P6, it complains: