Things · Games and communities
Road Sign Math (2026)
Road Sign Math rebuilt as an iPhone app that is the whole game, capturing a sign, reading its numbers, solving it and posting it, with roadsignmath.xyz as the place to see every sign on a map without the app.
Driving + Math = Fun.
- Status
- Active Being built or operated.
- Dates
- Started (Played since 2005, rebuilt in 2026)
- Where
- roadsignmath.xyz/
- Topics
- Play
- Page views
- 799 in the twelve months to Sep 30, 2026
- Latest evidence
- Latest commit, Oct 31, 2026
In October 2026 I rebooted Road Sign Math a third time, as an iPhone app that is the whole game. You photograph a sign from the passenger seat, the app boxes every number it can read, you check them, write your math on a keypad made for it, and post it. Everyone’s signs land on a feed, a map and a page for each player, and anyone can find another way to make a posted sign true. The first 16 signs are the ones from the blog, found by me, Tyler and Tammy from 2021 to 2025.
There are still no scores. I said so when we planned it: “The point system wasn’t a good idea. So I want to keep to the root which is a fun road trip game based on math and finding signs.” Instead there are badges, little road signs for a first sign, new states, a × in a way, all four seasons, and a few secrets.
roadsignmath.xyz is now the window onto the game for anyone without the app: the map of every sign, a page for each sign and each player, and no sign-in. It went live on October 30, 2026, replacing the blog, and on October 31 I submitted the app to Apple for a public TestFlight beta. Both the website and the app are open source.
The build #
- The iPhone app is the whole game. It reads the numbers on a photo of a sign on the phone, with Apple’s Vision, boxes each one, and turns what it reads into numbers a player can use, so 82nd St is 82 and EXIT 7B is 7.
- One equation checker is written in TypeScript for the server and ported to Swift for the app, and both pass the same test vectors. A way counts when its math is true and its numbers come from the sign. The math is kept as LaTeX and drawn with MathJax on the website and SwiftMath in the app.
- The server is Node and Hono in a Lambda Web Function behind CloudFront, with DynamoDB for the signs and players, S3 for photos and SES for sign-in mail, released on every merge to main. Its API is described in OpenAPI 3.1.
- Signing in is an email with a link or a six-digit code, with no password. Claude moderates posts, holding one only when it is clearly objectionable, looks at each profile photo first, and writes each photo’s alt text.
- Badges are little road signs worked out from the signs each time they are read, so a badge follows its sign. There are no points, no counts and no ranks.
- The website’s map is us-atlas’s Albers USA map, with each sign’s place projected and clustered on the server, so it needs no map provider. The app’s map is MapKit.
Swift and SwiftUI iOS 26 Vision MapKit TypeScript Hono AWS Lambda DynamoDB Claude TestFlight
Artifacts #
Files from the project itself, as they were kept.
The iPhone app #
The game from signing in to posting a sign, from October 30 and 31, 2026, the first two days of building it, on the simulator against a local copy of the server or the live one, with the 16 signs from the blog. The sample sign is one the app draws itself, for a simulator with no camera.
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The icon #
The math from the Twin Lakes sign, √(5 − 1) = 2, on a green guide sign.
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The sign-in email #
Under a “Driving + Math = Fun” sign, a button that signs in on the iPhone and a six-digit code to type instead. The code and link here are examples.
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Home #
The Latest feed, newest first: Tyler’s I-35W at 82nd Street sign from September 2025, its math, (90 − 82) ÷ 8 × 1 × 2 = 6 ÷ (10 − 7), and a button to find another way.
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The Map #
The 16 signs as pins and clusters across North America, filtered by year, with a search for a town, a number or a person.
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A sign #
“On the way to the airport,” my sign from August 2025 near Burlington, Vermont: its photo, its math, (25 − 1) ÷ 8 = 4 − 3 ÷ 3, and the ways found so far.
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Capture #
The camera in Passenger mode, after a shot of the sample sign. Every number it read has a yellow box, and it says it got five.
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Check the numbers #
Every number the camera read on the I-35W sign, boxed in yellow on the photo and listed below to keep or drop. It read 12, including the 902 on the minivan’s plate.
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Checking the numbers #
Fixing one number while checking what the camera read, with a close-up of where it read 82 in “82nd”. Letters next to a number are fine, so 7B counts as 7.
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Solving it #
The math keypad on the sample sign, with roots, powers and factorials. (90 − 82) ÷ 8 = 1⁷ uses every number on the sign, and the app says “It works! Both sides make 1.”
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Post it #
Naming the sign, with a suggested name, and its place, Bloomington, Minnesota, taken from the photo.
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Posted! #
The sign is on the map and the website, and two new badges came with it, Square Root and States: 2.
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Badges #
The shelves of road-sign badges, Firsts and Places, each with how it is earned and, once it is, the day and the sign that earned it.
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A player’s page, in dark mode #
My page in the app, with 13 signs in 5 states since 2021, my badges, and my signs as photos.
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Find another way #
Writing a second way on Tyler’s I-35W sign: (90 − 82) × 2 = 10 + 6. It works, and three numbers sit this one out.
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A profile photo #
Fitting a picture of a road and a sign into the circle that goes beside a player’s signs and on their page.
The website #
The new roadsignmath.xyz on October 31, 2026, where every sign posted from the app shows up, with no sign-in.
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Home #
“Find a sign. Make the math true.” The map of every sign on the US, with a card for Minnesota’s two signs, and who’s playing: me, Tyler and Tammy.
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A sign #
Tyler’s I-35W at 82nd Street sign on the website: the photo, the math, the ways found so far, the numbers, a map pinned on the town, and nearby signs.
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A player’s page #
My page on the website, with my badges and my signs on the map.
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Join the beta #
The website’s section for the app, with a link to join the iPhone beta through TestFlight.
Activity #
44 commits, all with Claude, the first on Oct 30, 2026.
The latest weeks with activity
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Week of Oct 26, 2026 44 commits, all with Claude
- Tinylytics events on the ways to the app (#24)
- Docs: player links open the app; the public beta's steps as they stand (#18)
- A Privacy page, linked from every page's footer and in the sitemap (#23)
41 more commits
All activity, week by week. Who made each commit is from its author and co-author lines.
Sources and evidence #
Observed daily from GitHub, sitemaps, feeds, the Internet Archive, and Tinylytics. Evidence never sets a status.
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roadsignmath.xyz/ website
- Sitemap: 21 pages, newest change Sep 2, 2025
- 799 page views from Oct 1, 2025 to Sep 30, 2026, counted by Tinylytics
- Observed Oct 31, 2026
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jthingelstad/roadsignmath.xyz implementation
Road Sign Math: the website and the server behind it. Driving + Math = Fun.
- Repository created Oct 30, 2026 (a development record, not a launch date)
- TypeScript, Shell
- Latest commit Oct 31, 2026; 25 commits on main between Jul 1, 2026 and Oct 31, 2026
- Observed Oct 31, 2026
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jthingelstad/roadsignmath-ios implementation
Road Sign Math for iPhone. Driving + Math = Fun.
- Repository created Oct 30, 2026 (a development record, not a launch date)
- Swift, Shell
- Latest commit Oct 31, 2026; 19 commits on main between Jul 1, 2026 and Oct 31, 2026
- Observed Oct 31, 2026
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roadsignmath.xyz/privacy reference
Commits and publications per month, last twelve months.
Connections #
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Road Sign Math (2021) was succeeded by Road Sign Math (2026)
In October 2026 the 16 signs on the blog became the first signs in the Road Sign Math iPhone app, and the new roadsignmath.xyz replaced the blog. Source
History #
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milestone
Road Sign Math’s public beta
The Road Sign Math iPhone app goes to Apple for a public TestFlight beta, and roadsignmath.xyz links anyone with an iPhone to it. Source
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launch
Road Sign Math reboots as an iPhone app
The third reboot makes Road Sign Math an iPhone app that is the whole game, and a new roadsignmath.xyz, the map of every sign, replaces the blog. Its first 16 signs are the blog’s. Source