- New Nightmare Scenarios - 19 July 2026
Added new nightmare scenarios along with small bug fixes.
- Dev Diary 9 - 8 June 2026
Okay! This week will focus on the development of a market-specific AI for the 2nd nightmare scenario. As discussed last week, all stocks follow a sin function; that is, a wave-like function that goes up and down. The timing of the increase depends on two features during the run-in period:The price difference between the beginning and the end of the run-in periodThe difference between the highest and lowest prices during the run-in periodAs discussed in Dev Diary 7 (link), a market-specific AI aims to provide insight into the underlying truth and beat the default AIs, it is not intended to implement the most optimal trading strategy. In this context, our first attempt at the market-specific AI will implement the following high-level trading strategy:On turn 1: Invest in a stock with the following characteristics from the run-in period: (1) did not change much with (2) stable prices.If th…
- Dev Diary 8 - 1 June 2026
This week will focus on the initial development of the 2nd nightmare scenario. For this dev diary, we will begin work on a different market-condition with a fundamentally different approach. As outlined when setting up the 1st nightmare scenario (Dev Diary 5), the first step for designing a scenario is determining the expected change in stock prices. In this situation, a slightly different representation will be considered:current stock price * (x - (stock dividend))x is approximately the overall expected return. During the “run-in period” prior to the first turn, x will be randomly selected from a uniform distribution between -0.05 and 0.1. After the first turn, x will be determined from a sin function (returning expected overall returns between -25% and 25%). The sin function will be shifted based on the relative characteristics of the stock price prior to turn 1. Specifically, the ba…
- Dev Diary 7 - 26 May 2026
Welcome back! In the last diary, we finished the initial draft of the underlying truth for the first nightmare scenario. Today we will begin working on a market-specific AI. In general, the market-specific AI has two primary goals:Provide players with insight into the underlying truth.Beat the default strategies common across each market scenario.Importantly, the market-specific AI is not designed (and usually is not) the clearly optimal trading strategy.There are two main observations for recapping the underlying truth:At similar prices, stocks with a low dividend will have a higher overall return than stocks with a high dividend.A ‘bear market’ (or an ~40% decrease) is increasingly likely as the number of stocks at or above $145 increases. A couple of important points on the bear market:A bear market is ~13% likely with 2 stocks, ~40% likely with 3 stocks, and 62% likely with 4 stocks…
- Dev Diary 6 - 11 May 2026
Welcome back! The past week was busy with work and then a nasty head cold (which is lingering), but it is time to get back to developing a new “nightmare” market condition. At the end of the prior diary, we settled on an approach for the average change:current stock price * (0.10 - (stock dividend) ^ (100 / current stock price)) with the general intent of favoring stocks with lower dividends unless their price was too high (or a high dividend stock had too low of a price).At this point, we will start testing the market condition in the game. This was my first attempt at implementation after the week off.It was wrong. The issue was raising (0.10 - stock dividend) ^ (100 / current stock price) rather than only stock dividend, which is always positive. After correcting this issue, we observe a more reasonable and expected stock behavior. This iteration emphasizes the importance of continua…
- Dev Diary 5 - 27 April 2026
Welcome to Dev Diary 5! Today we will begin the development of a new “nightmare” market condition. This process is usually non-linear and involves a large amount of trial and error. As such, this process will take multiple diaries, may suddenly backtrack, or end up in unexpected places. As a warning, this material will be relatively technical. The goal is ending up with a market condition that is unique and has a nuanced solution (rather than simply broad-based index-like investing). To get to this type of iterative work, this diary will primarily introduce background information on the underlying game processes.Defining prices changesIn developing a new market condition, my first step centers around defining the expected changes in stock prices. Mathematically, this is represented with:price change = average change + noisewhere noise is randomly determined from a continuous Uniform dis…
- Dev Diary 4 - 20 April 2026
Welcome to dev diary 4! The diary celebrating release day, and the last diary covering the market conditions in the demo: Advanced difficulty with a moderate theme (Advanced/Balanced). The plan for future dev diaries is discussed at the end. Deciphering the Advanced Market-Condition in the DemoIn contrast to previous diaries, the market-specific AI has a more discernible strategy in this condition because it primarily revolves around conditions on turn 1: (1) it will put most money into a stock close to $100, and (2) it buys one of the cheaper stocks, if able. On subsequent turns, the market-specific AI usually buys one of the two stocks bought on the first turn, if able.Importantly, as illustrated in the screenshot, the latter observation is not a strict logical condition. The AI sometimes buys the cheapest stock. Other times it buys a cheaper, but not cheapest, stock.This behavior sug…
- Dev Diary 3 - 13 April 2026
Welcome to Dev Diary 3! Today’s topic will be the second market condition included in the demo: Moderate difficulty with an Esoteric theme (Moderate/Esoteric). In contrast to Dev Diary 2, we will walk through the market condition to infer an optimal trading strategy.This is intimidating. Where to start first?Since we need to start somewhere, let’s look for similar relationships as seen in last week’s diary on the Easy/Aggressive market condition: do changes in one stock predict the changes of another stock? As illustrated below, these relationships are completely flat (in other words, changes in one stock do not predict changes in other stocks). However, the screenshot has an interesting characteristic: the changes for all of the stocks are mostly bounded above and below. This indicates that something may be bounding the price of each stock. However, the prices of the stocks are also bo…
- Dev Diary 2 - 6 April 2026
Welcome back! Today we will walk through the first of three market conditions included in the demo: Easy difficulty with an Aggressive theme (denoted as Easy/Aggressive).Okay. So what is the underlying truth in this scenario? As described in the Dev Diary 1, because the difficulty is easy, the underlying truth depends on only a single stock:ABC and QE will increase if BCUC increased on the previous turn.ABC and QE will decrease if BCUC decreased on the previous turn.The magnitude of the changes for ABC and QE are approximately proportional to the change in the BCUC price from the previous turn.When playing a game, these relationships may be visible when only the BCUC, ABC, and QE are selected in the figure, although the differences, especially for BCUC, are relatively small.While the relationship can be identified within the game, it is also visible in the simulation analysis of the str…
- Dev Diary 1 - 30 March 2026
Welcome! This diary will introduce Line Go Up, the key mechanic, and the design philosophy behind the game.What is Line Go Up?Line Go Up is a game about making money through the knowledge of which stocks will go up and which stocks will go down. Fundamentally, this requires distinguishing the signal from the noise and identifying the underlying truth around which stock prices fluctuate. Once the truth is identified, you can translate it into an optimal trading strategy, make money, and, more often than not, win the game.However, the market conditions, which are selected at the beginning of each game, define the underlying truth. So, even if you master one market condition, other conditions will present new and unique challenges to decipher.What does a game look like?Each turn, players simultaneously submit buy and sell orders, and the orders are revealed only when every player is ready…
