“Emily Oster is the founder and chief executive of ParentData and a professor of economics at Brown University.” This article appeared in The New York Times, May 10, 2026
In the past several years, about three dozen states have instituted phone bans in schools, and more are likely to follow. These bans have been trumpeted as game changers. Anecdotal reporting points to more books being checked out from school libraries and more students engaging with one another in the hallway. “How the Phone Ban Saved High School,” reads one headline. At the same time, respected academics have suggested that the arrival of phones in schools is linked to large test score declines in countries around the world.
It was, therefore, surprising to many people when a paper this week showed that phone bans had a very minimal impact on student behavior and academics in a nationwide sample of schools. Phone usage went down, and teachers liked the policy (all good), but test scores didn’t change much, disciplinary infractions increased in the short term and there was no demonstrable effect on bullying or student attention. Basically, not much changed.
This finding should not have been as surprising as it was. Based on what we know about phones and education, it is not realistic to expect phone bans to have enormous impacts on academic outcomes. But that doesn’t mean that they are a bad idea, or that they should be walked back. Instead, we need to approach this topic with more realistic expectations, a richer approach to what counts as a positive outcome and more help for families and schools.
The expectations for phone bans were poorly calibrated, largely because the data on which some of the more extreme claims about phones is based is subject to considerable biases. For example, a paper published last fall argued that increases in phone usage were tied to large reductions in test scores in many countries between 2012 and 2022. The study found bigger drops in test scores in countries with greater smartphone adoption. But it turns out that those were alsothe countries that had longer school closures during the Covid-19 pandemic. Phones may have played a role in driving test scores down, but since we know school closings mattered for academic progress, too, the emphasis on phones overstates their role.
There is also plenty of data showing that children who spend more time on social media do worse in school, but they tend to come from households with fewer resources. It may also be that problems in school are contributing to social media use, rather than the other way around. Finally, given that a lot of phone usage is outside of school, it’s unclear if these results would really apply to phone bans in school.
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The paper out this week takes a better approach, looking at how test scores and behavior varied over time as schools restricted phone use by introducing Yondr pouches that lock away phones during the day. An earlier paper, which looked at variation across school districts in Florida as some introduced phone bans earlier than others, found similarly small effects on test scores. These are the studies we should be focusing on.
Over the next several years, we will get more data exploring these questions. I expect a cottage industry of papers on school phone bans — and we’ll probably also start to see results from school districts that change technology in other ways (for example, taking computers out of early childhood classrooms). We should expect to see similar results.
It would be a mistake to interpret these findings as a sign that we should forget about phone bans altogether. There are no magic bullets in education. Improving student learning is a game of inches, not miles. There is no clear positive reason for students to have phones in the classroom. No phones should be the default, and to introduce phones, we’d want to see evidence that they meaningfully improve learning or help in another way. None of that appears in the data. On the flip side, I think the knee-jerk reaction to also remove all computers and tech is an overstatement and unrealistic.
Instead, we need to alter our expectations. Phone bans may be helpful in some ways, but they aren’t a cure-all, and that shouldn’t be the bar for success.
Second, we have to get better data. Test scores are easy to measure, but a lot of the discussion around phone bans focuses on the experiences of students, how they interact with one another and whether the classroom feels engaging to both students and teachers. We should be measuring those outcomes systematically. I do not allow my students to have phones or laptops in my classroom, because screens affect their participation and, quite honestly, it’s demoralizing to look out at a classroom of kids scrolling on their phones. I’m guessing other teachers feel similarly; we should figure out how to measure and evaluate this, too.
Finally, we need to find a more helpful approach for schools and parents to manage technology. We’ve sent parents and schools messages that are simultaneously fear-inducing (“phones are ruining your children”) and overly optimistic (“phone bans will make it better”). Neither of these is true, and it’s time to move to something that promises less, but delivers more.
For schools, that may mean keeping phone bans and making additional changes, like modifying laptop use in some classrooms, while recognizing that technology is part of modern life and not the enemy. It could also mean focusing on resources and instructional support that will actually move the needle on test scores.
On the parental side, we need fewer blanket warnings about the dangers of technology and more help drawing appropriate boundaries for our kids. Teenagers absolutely need rules and restrictions on their phone use, and they need their parents to set those — and parents need help doing that. Phone bans promised an easy fix, but they aren’t magic. The faster we realize that, the faster we can make realistic progress.
The first version of NetHack was released in 1987 as a heavily modified descendant of Hack, itself based on Rogue, a Unix-era experiment built for character-based terminals around 1980. The term “roguelike” later emerged in the early 1990s. This is also when Usenet communities, like rec.games.roguelike, were founded. Players and developers gathered there to trade ideas, variants, and philosophies inspired by Rogue’s design.
Screenshot of Rogue courtesy of the Retro Rogue Collection. The player “@” can be seen above a food item “%” and a jelly monster “J”.
That lineage helps explain something unusual about the genre. NetHack was developed collaboratively over networked systems before most people even had internet access. Angband required a coordinated relicensing effort decades later just to become fully open source. And Pixel Dungeon was declared “complete”… and then immediately forked by the community into dozens of new games.
Recently, I built a small experiment that turns a GitHub repository into a roguelike dungeon. That idea came from the gaming genre that has been evolving in the open for decades, shaped as much by players as by developers. Many of the games that defined roguelikes are still actively maintained today, with contributors refining systems, debating mechanics, and layering in new ideas over time.
That same spirit shows up in events like the 7DRL challenge, where developers build a complete roguelike in seven days, and in the annual Roguelike Celebration, which brings the community together to share ideas, research, and experiments. The genre thrives in these spaces, where iteration is fast, ideas are tested in public, and even small projects can leave a lasting mark.
Here are 10 open source roguelikes you can study, contribute to, and play for hours, until you’ve totally lost yourself. Most of them started small. None of them stayed that way…
Cataclysm: Dark Days Ahead drops you into a world where everything has already collapsed. Cities sit abandoned, labs hum with leftover experiments, forests reclaim the edges, and the roads lead nowhere good. You scavenge through the wreckage while hunger, injury, weather, and time keep pressing in. The world runs continuously, shaped by a huge contributor base that keeps adding systems and interactions. Every building has a story baked into it. Most of them end with you running.
It started as a fork of Cataclysm and never really stopped growing. Over time, contributors kept layering in new systems, interactions, and edge cases until the simulation reached a kind of sprawling completeness. You can wire in cybernetics, mutate into something barely recognizable, or assemble an armored vehicle from whatever you can salvage. None of it is scripted. It all emerges from the rules underneath. The level of detail even spills into the community, where players argue about nutrition, crafting logic, and what should realistically exist.
🛡️ Fun fact: Its simulation is so deep that contributors regularly debate real-world topics like nutrition, physics, and crafting logic in pull requests.
NetHack was first released in 1987 as a fork of Hack, the 1984 game that grew out of Rogue’s dungeon-crawling experiments. It drops you into a dungeon packed with shrines, traps, cursed gear, and monsters that seem personally invested in your downfall. Every object follows its own rules, and those rules collide in ways that feel almost vindictive. After decades of contributions, the game is dense with edge cases, hidden mechanics, and bizarre outcomes, so curiosity rarely goes unpunished. The deeper you go, the more the dungeon seems to anticipate whatever terrible idea you are about to try next.
⚔️ Fun fact: The “Net” in NetHack comes from how it was built. It’s one of the earliest games developed collaboratively over the internet, with contributors coordinating across networks long before modern open source workflows.
Dungeon Crawl Stone Soup unfolds across a network of dungeon branches, each tuned to test a different kind of mistake. Lairs full of beasts, vaults packed with threats, deeper levels that stop pretending to be fair. You choose a species, a background, maybe a god to follow, and your choices carry through everything that comes after. Magic, religion, and skills all pull in different directions, so builds don’t settle—they evolve under pressure.
You can play offline or on public servers, where other players’ ghosts appear and people watch games unfold in real time. It’s a shared space as much as a dungeon. Resources stay tight, every decision stacks, and you deal with the outcome.
🛡️ Fun fact: Dungeon Crawl Stone Soup is what happens when a community refuses to let a project stall. Forked in 2006 to revive a slowing codebase, it’s still evolving today—sometimes by adding features, sometimes by deleting them.
Angband stretches downward from a quiet town into a massive dungeon tied to decades of development. Each level pushes deeper toward a final confrontation that has defined runs for generations. A steady contributor base keeps refining mechanics while variants and forks branch off in different directions. The structure stays familiar, but the scale and history give it weight.
It traces its lineage back to Moria in the 1980s, and it didn’t stay contained for long. Forks spun out into dozens of variants—some tweaking balance, others rebuilding systems or shifting the setting entirely. Some stay close to the original, others turn it into something barely recognizable. Ideas move between them, get reworked, and show up somewhere else a few years later.
Despite its age, it’s still being updated. Around it sits a community that keeps things moving—ladders, forums, live servers where people watch runs unfold in real time.
⚔️ Fun fact: Angband didn’t start fully open source—it took a coordinated relicensing effort in 2009 to get there. Decades of contributors had to align to make it happen, turning one of the oldest roguelikes into something the community could truly take forward.
With the transition to GitHub, Angband’s development split into distinct branches: a stable mainline and experimental offshoots. This shift led to what David L. Craddock describes as an “explosion of productivity,” with new versions appearing almost nightly. These development branches functioned like a “secret lab,” where the dev team’s “mad scientists” could freely experiment—building and discarding features without risking the integrity of the official release.
This branching model not only accelerated development but also made experimentation sustainable. (Craddock, Dungeon Hacks)
Brogue presents a dungeon built with clarity and intent. Rooms connect in ways that funnel you into decisions you cannot ignore. Light drops off into darkness, fire spreads through terrain, gas drifts, and the environment joins every fight. Each floor feels deliberate, with just enough unpredictability to keep you alert. When things go wrong, you can trace the moment it started.
That clarity has also led to a surprisingly active mod scene, with dozens of community variants experimenting on top of the same foundation—some adding new monsters and items, others reworking pacing, visuals, or the feel of a run entirely (see the full list).
🛡️ Fun fact: The original Brogue stopped receiving official updates years ago, but the community didn’t leave it there. Development continued as Brogue Community Edition, with contributors picking up the codebase and still shipping new releases today.
Pixel Dungeon is structured as a series of quick-hit layers. Sewers give way to prisons, then caves, then worse. Every level adds a small twist—a trap, a new enemy, a bad surprise behind a door you probably should not have opened. Built as a free passion project with no monetization hooks, it leans on tight design and fast pacing. Runs are short. The urge to start another one is not.
⚔️ Fun fact: Pixel Dungeon went open source in 2014 and was declared “complete” a year later. The community took that as a starting point, not an ending… spinning up dozens of forks and variants that are still being updated today.
Shattered Pixel Dungeon takes that structure and pushes it further. Regions feel more distinct, enemies and items open up viable paths, and regular updates keep reshaping the experience. The dungeon keeps growing without losing its pace. Community feedback feeds directly into development, so the world keeps shifting under players who thought they had it figured out.
🛡️ Fun fact: Shattered Pixel Dungeon started as a small balance mod and quietly turned into a full game over years of continuous updates. A decade later, it’s seen dozens of releases, millions of downloads, and is widely considered one of the best open source games out there—all while sticking to pure roguelike principles with no permanent upgrades, just better decisions each run.
DRL runs through military bases and hell-infested corridors filled with familiar threats and very loud intentions. Tight levels, heavy weapons, and encounters that escalate fast. The structure stays turn-based, but the pressure feels immediate. Built in Free Pascal and fueled by 90s shooter DNA, it delivers short runs that hit hard and end fast if you hesitate.
DRL is a fast and furious, coffee-break length roguelike game that is heavily inspired by a certain popular 90s FPS game.
⚔️ Fun fact: DRL started life as “Doom, the Roguelike,” before a trademark notice forced a rename—ironically speeding up its transition to open source. It’s been evolving since the early 2000s and still gets updates today, all while turning one of the fastest FPS games ever made into a turn-based roguelike that somehow keeps the same intensity.
KeeperRL begins underground, where you carve out rooms, lay traps, and build a dungeon designed to break incoming heroes. The surface world pushes back with raids, while your minions train, craft, and occasionally cause problems of their own. You can step in directly for tactical combat or let the systems play out. Fire spreads, creatures react, and the dungeon develops a personality that reflects your decisions.
🛡️ Fun fact: KeeperRL leans hard into its open source roots. You can buy the full version by donating to wildlife charities, grab a completely free ASCII build if you prefer a terminal experience, and even get help from the developer compiling it yourself.
HyperRogue spreads across dozens of strange lands where geometry refuses to cooperate. Paths diverge in unexpected ways, space expands faster than expected, and returning to a familiar spot takes more precision than it should. Each region introduces its own rules, enemies, and hazards, all layered on top of that shifting foundation. Movement alone becomes a skill you have to learn under pressure.
HyperRogue takes the familiar loop of a roguelike—moving, surviving, collecting, and adapting—and places it in a world where the rules of space no longer behave as expected. Built on hyperbolic geometry, its world expands faster than intuition can track, making navigation as challenging as combat. Paths that seem parallel drift apart, returning to a previous location requires deliberate precision, and positioning against enemies forces you to learn a new spatial logic under pressure. Each of its many distinct regions adds unique mechanics, hazards, and creatures on top of this unstable foundation, constantly reshaping how you approach the game. Despite its abstract design, the core remains direct: gather treasure, avoid being overwhelmed, and push deeper as the difficulty scales. The result is a roguelike that feels less like exploring a dungeon and more like learning the rules of an unfamiliar universe one mistake at a time.
⚔️ Fun fact: HyperRogue doubles as a long-running research project. Its developer, @ZenoRogue, continuously experiments with hyperbolic geometry, adding new lands, mechanics, and systems that explore how games behave when the rules of space itself change.
Maintained by community
What stands out across all of these projects is how active they still are. People are adding systems, revisiting old decisions, and pushing mechanics into weird corners just to see what holds up. Some have evolved with updated graphical interfaces, others stay true to their terminal roots, and a few let you switch between both. You see the same thing happening around them too, in tools like Ghostty, Charm’s suite, and Ratatui, where the terminal keeps getting stretched in new directions.
Tight loops, visible systems, communities that don’t drift away. That’s what keeps roguelikes here—and the CLI is built on the same foundation.
These projects don’t die. They just get forked.
Thanks for reading, adventurer. May your next run end slightly better than the last! ⚔️
11 Special bonus roguelike-like game
YARLM (Yet Another Roguelike Lee Made) called Snakelike, a daring mix of Rogue and Snake that I conjured using GitHub Copilot for the umpteenth annual 7DRL Celebration. Ssseee if you can beat my high ssscore. 🐍
The New York Times recently reported on the growing unhappiness among students and parents with education technology:
Los Angeles parents are fed up with schools loading up students with laptops and tablets, and assigning schoolwork on a slew of apps.
Some families, who had decided against giving their children screens at home, told school board members that they were appalled to find young students using school-issued devices — even in kindergarten. Some parents complained that their children were able to play video games or watch social media videos during school.
The edtech industry ignores at its own peril just how disenchanted students have become with their devices, especially after virtual schooling through the pandemic. Before the pandemic, it often felt novel and exciting to unload the laptop cart. Students got a little more dopamine and gave a little more attention simply because of screens.
Several years later, kids feel very differently. You can see the difference even when news outlets report on classroom use of artificial intelligence, surely the buzziest new education technology. Those articles invariably contain rapturous descriptions of personalization, dynamism, and the future. Yet you’ll see, without fail, a field photo of kids looking like they have been dosed with a veterinary-grade tranquilizer.
Credit: Adriana Heldiz/CalMatters
Edtech needs a new melody.
Teaching is the work of composition. Teachers compose the resources in a classroom—including education technology, but also paper, textbooks, questions, explanations, whiteboards, other students, the physical space, etc.—into experiences that help students learn. I find it helpful to think of those resources as musical instruments and their composition as a melody.
In many classrooms, students find the melody pretty dull—regardless of the teacher’s use of education technology. Few would argue this is a pleasing melody, for example. Every note is pure teacher explanation for a 20 minute segment of class.
Here is a different melody. Many teachers are enthusiastic about whiteboards and their potential for quick formative assessment. The teacher poses a brief question; students answer on whiteboards; the teacher responds to the class results with an explanation or summary followed by another question.
In that melody, the students hear several different notes—whiteboards, teacher questions, teacher explanations—all played to direct student attention towards learning.
Digital technology frequently produces as monotonous a melody as a teacher speaking endlessly in front of a blackboard. In the sort of experience reported in The New York Times above, you’ll often see the teacher explaining a task, then sending students off to work by themselves on their computers, often in silence, after which the teacher collects the laptops and ends the activity. The experience is digital, but the music is still a dirge. These devices are some of humanity’s most incredible achievements, but when students use them in schools they often hear only two notes—teacher explanation and screens.
We must learn other melodies for education technology. As one example, I taught a class last week here in Oakland, CA, using our curriculum and I can tell you that kids were on devices for no more than five minutes at a time before I brought them together to a) set up the next task, b) ask selected students to share their ideas, c) ask the class to help settle a dispute, d) do a closing assessment on paper, etc. The composition looked a lot like this.
In one of my favorite moments, students heard multiple notes simultaneously—a chord. Students were matching different sets of cards together to make equal products.
There were hundreds of digital cards around the classroom. With the push of a button, the software analyzed which card was the hardest for the class to group. I told the class, “This card is our hardest. Show your neighbor where you have placed it. See if you agree.” Students passed their laptops across the table to their classmate as an object of conversation just as you or I might a coffee table book.
This is a challenging way to teach, in part because computers incur heavy switching costs. It takes quite a lot longer to log into a laptop than it does to “log into” a paper handout or a class conversation. As we segued from computers to a class conversation, I begged the kids to only close their laptops halfway, because if they closed it all the way, the district laptops automatically logged them out and we’d lose significant time logging back in. Those costs all mean education technology needs to bring more value to a learning experience than any analog substitute. In my case, I used a digital card sort because it could find out the most challenging card with speed and accuracy that I can’t match on my best day with paper cards.
“How much screen time is too much?” is an important question, but just one of many. We should also wonder what students do with their time on screens and what purpose that work serves. With so much edtech today, the instruments are shiny and new but the melody is still monotonous. We should wonder how we can play a more interesting melody with computers in class, kids switching in and out of them as easily as switching between people in a conversation, between pages in a book, between instruments in a symphony called learning.
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Today's maths comes to you courtesy of Wembley Master Chef, 44 Harrow Rd, HA9 6PG.
This Pizza Deal poster appears in the window.
That's good value, isn't it?
Well let's check...
First let's scale that down to the cost of one pizza, not two.
Diameter
Price
7 inch
£3.75
9 inch
£4.95
12 inch
£6.95
15 inch
£8.45
We can try to find the best value pizza by calculating price per inch.
Diameter
Price
p per inch
7 inch
£3.75
54p
9 inch
£4.95
55p
12 inch
£6.95
58p
15 inch
£8.45
56p
This suggests the 7 inch pizza is the best value at 54p per inch.
But they're all remarkably close, each just over 50p per inch.
It almost looks like this is how they determined the prices.
But pizzas aren't linear, it's the area that increases.
Please ignore everything in the previous table, it's mathematical rubbish.
We could try to estimate the area by counting the number of pepperoni slices on each pizza.
Diameter
Price
no of slices
p per slice
7 inch
£3.75
12
31p
9 inch
£4.95
26
19p
12 inch
£6.95
32
22p
15 inch
£8.45
35
24p
This suggests the 9 inch pizza is the best value at 19p per slice of pepperoni.
The 15 inch pizza might look more packed but its slices are 22p each.
However this is also mathematical rubbish because you can't just go by photos.
In particular the 12 inch and 15 inch pizzas are shown pretty much the same size, and they're not.
My suspicion is that these pizza images aren't real, merely AI conjuring.
So we can't use fictional pepperoni slices to calculate best value either.
What we should be doing is calculating the area of each pizza in square inches.
It's good old A=πr².
Diameter
Price
Area
p per sq in
7 inch
£3.75
38 sq in
10p
9 inch
£4.95
64 sq in
8p
12 inch
£6.95
113 sq in
6p
15 inch
£8.45
177 sq in
5p
That's more like it.
The 7 inch pizza is the worst value at 10p per square inch.
And the 15 inch pizza is the best value at 5p per square inch.
This is because a 15 inch pizza is a lot bigger than it sounds.
Diameter
Area
compared to 7 inch
7 inch
38 sq in
×1
9 inch
64 sq in
×1.7
12 inch
113 sq in
×3
15 inch
177 sq in
×4.7
A 15 inch pizza is almost 5 times the size of a 7 inch.
But at Wembley Master Chef the price is only roughly double.
So if you want best value cheesy pepperoni stodge, go large.
I also checked the cost of buying these pizzas online. Ouch.
Diameter
Shop deal
Online order
7 inch
£3.75
unavailable
9 inch
£4.95
£8.90
12 inch
£6.95
£11.90
15 inch
£8.45
£14.90
The last column is even if you order online and collect it yourself.
In each case you're paying 75% extra for the privilege of ordering online.
So at the end of all that, two conclusions.
1) Larger pizzas are much better value.
2) Don't order online.
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