Digital products
and useful systems
Selected product, design and web work, from shop-floor tools to evidence-led studies of small questions.
Begin with PaperWatcherPublic service · paperwatcher.co.uk
Know before the till does. A single source of truth for UK newspaper prices, barcodes and the changes coming next.
“The newspaper price is changing on Monday” sounds simple. It has to reach the EPOS, the shelf labels, the ordering system and the staff before a customer is charged the wrong amount.
Newsagents and independent retailers historically tracked this by hand: trade emails, spreadsheets, and someone remembering. Miss an update and you get till discrepancies, corrections, and a customer who trusts you slightly less.
The data existed. What was missing was somewhere to look it up quickly, see what is coming, and act before Monday.
Product directionTurned a recurring trade annoyance into a service with a clear, narrow promise.
Data designModelled prices as dated events so history, barcode changes and audit trails all fall out of one store.
EngineeringBuilt the ingest pipeline, alerting, exports, JSON API and a toolbox of 87 retailer utilities.
OperationsRuns as one process on one small server, with streaming off-site backup and loud failure modes.
Local-first product · propertill.app
A proper till, in the browser you already have. No account, no subscription, and no sales record leaving the counter it was taken on.
Small-business EPOS is usually rented: a monthly fee, a terminal you cannot replace, and a sales history held somewhere you have to ask for. Proper Till inverts all three. It runs in the browser already on the counter, and the shop's own record never leaves it.
For a market stall, a village shop or a Saturday pop-up, the realistic alternative to a subscription till is a cash tin and a notebook. The subscription is not just the cost: it is the card reader you must buy, the account you must keep, and the export you cannot get once you stop paying.
So the promise is deliberately narrow: this is a till, not an accounting system. Every boundary it will not cross is written into the product itself rather than left for a customer to discover.
Product directionHeld the promise narrow: a till, not an accounting record. Every boundary it will not cross is written into the product's own wording.
ArchitectureMade the browser the whole system: no backend, no account, and money in integer pence from the tile to the receipt.
ReuseLifted the money, VAT and sale-lifecycle rules out of an earlier product against a written reuse matrix, carrying their test cases rather than their code.
DeliveryLive at propertill.app: reachable and free, honest that it is new and unproven on a busy trading day, with the open VAT questions still tracked rather than quietly assumed closed.
Windows desktop tool · open source
A read-only storage inventory for Windows. It scans a drive or folder, writes every file and folder to reports you can keep, and says plainly when a scan could not see everything.
Disk-space visualisers are good at “what is big right now?” on screen. StorageInventory does a slightly different job: a complete inventory you can keep, with every file and folder written to reports you can sort, filter and archive.
An inventory is only as useful as your sense of how much of it to trust. The awkward case is the folder that could not be read. Here it becomes a row in the errors report, and every total that includes it is marked as a lower bound: at least this much, possibly more.
It reads only the metadata a folder listing returns, such as names, sizes, dates and attributes, and never opens file contents. It ships as one self-contained executable that needs no installation, no administrator rights and no separate .NET runtime, with no telemetry, analytics or update checks.
The progress bar follows the same rule: while the total is unknown, it does not invent a percentage.
What it writesOnly in the report folder you choose, which must sit outside the folder being scanned. Reports are created as new files named with the date, time and a random run ID, so an existing file is not replaced.
LinksJunctions, symbolic links, mount points and cloud placeholders are listed and not intentionally followed. The README and security review document the narrow cases that remain, such as a folder swapped for a link in the middle of a scan.
PrivacyReports hold file and folder names, full paths, sizes and timestamps, which can be private. Review them before sharing. A report folder inside OneDrive or another synced location will be uploaded by that service.
CountingSizes are file lengths, not space used on disk. Hard links are counted once per link, and alternate data streams are not counted.
Not in 1.0Keeping scans as snapshots and reporting what changed between them is planned for 1.1, with no date. It is on the roadmap, not in this release.
The release is one StorageInventory.exe for Windows 10 and 11 on x64.
The release notes give its SHA-256, and a clean build from the tagged source
is documented to reproduce the same hash.
The executable is not code-signed, so Windows SmartScreen may warn the first time it runs. Check the hash before choosing to run it anyway. Known limitations are listed in the README and the security review.
Evidence-led web study · whyisthemoonsobig.com
A small question taken seriously. An interactive study that separates how big a low Moon looks from how big it is, shows every receipt, and will not pretend the science is more settled than it is. Then it hands you a clicker.
A low Moon can look enormous. The study starts by pulling that word apart: how big the Moon is reported to look is not its physical diameter, and not its measured width in a controlled photograph. Five measurements, one coat.
Most answers to this question pick one tidy cause. The research does not allow that. No single perceptual mechanism currently gives an uncontested, complete explanation of the natural Moon illusion, so the page lists the proposed contributors as proposals, not verdicts, and every demonstration carries a line saying what it does not show.
Every factual sentence comes from an independently reviewed claim ledger, and the site’s own tests reject single-cause phrasings before they can ship. Nothing loops, nothing auto-plays past three seconds, and reduced motion removes all of it with the meaning intact.
A complete idle clicker where the currency is Bigness: how enormous the Moon is reported to be. You employ departments, and every department produces reports. Not one of them produces a larger Moon.
Play Moon Clicker
Play the game
“The Moon Enlargement Division has never enlarged the Moon.”
It is the study’s answer turned into a mechanic. The article separates how big the Moon looks from how big it is; the game lets you industrialise the first while the second never moves. Telescopes crop the sky, a perspective manipulator moves the observer, a PR agency does what PR agencies do, and the Moon says it has not changed size at every opportunity.
It is found rather than advertised. Poke the Moon at the end of the article and a Bigness counter appears; keep going and the Moon suggests, not warmly, that somebody else could be doing this. Readers who never play carry about three kilobytes of it.
The game obeys the study’s rules: it may state no fact the article has not already made. Its engine is pure and deterministic, with no page, clock or randomness inside it, which is what lets hostile saves, keyboard-only play, reduced motion and a missing script all be tested end to end.
EditorialClaims first, copy second: every factual sentence traces to a reviewed claim, and the site’s tests refuse single-cause answers and words like “solved”.
InteractionDemonstrations that teach by doing: a horizon comparator, a framing model that is plainly “not your phone”, a crop test, each with its limits beside it.
Art directionA lunar calibration desk: a chalk Moon breaking a sodium horizon, and a perforated ribbon that locks onto its width.
GameMoon Clicker, from economy and writing to a deterministic engine, offline progress, versioned saves and an installable shell.
Evidence-led web study · whydoesrainsmellgood.com
One raindrop, followed onto dry ground. An interactive study of a smell nearly everyone loves, built to keep apart two words the internet keeps merging, and to say plainly where the evidence stops.
Rain can help move material from a suitable surface into the air. That physical transport does not give every storm one fixed smell, molecule or story, and the study is built around holding both halves of that sentence at once.
Petrichor and geosmin are routinely used as one word. They are not. Petrichor is the name Bear and Thomas proposed in 1964 for an odour released when dry rocks, clays and soils are moistened; geosmin is one specific earthy-smelling compound made by microorganisms such as Streptomyces. The page gives the difference its own section, stamped Not the same word.
Where the review could not verify a general cause, for the smell before rain or off a warm pavement, the claim is blocked, and the site says so on its receipts page rather than letting it quietly disappear.
The First Drop walks one impact through dry surface, impact, trapped air, a bubble at the interface, and the burst that throws up aerosols. It runs from buttons or arrow keys, announces every step, and a full run takes under three seconds. It is labelled for what it is: an illustrated experimental mechanism, not a chemical inventory, a weather model or a smell simulator.
The daft parts are allowed to be daft because they carry nothing. Catchable drops, a pokeable worm, a button that tries to merge the two words and watches them spring apart: none of them states a fact the page has not already made.
A tiny garden that grows on its own. Plant something, let it rain, watch the worms work the soil underneath, and find out what turns up. Rain on ground that has been dry a while gives petrichor, the rare currency, and the one place the study’s subject becomes the mechanic.
Nothing punishes absence: no streaks, no timed events, nothing daily. The field notes can only quote the study’s approved wording, looked up by claim, and the blocked claims are unreachable by design. The worm takes credit for the rain. He is wrong.
Visit Petrichor GardenEditorialKept petrichor and geosmin apart, and published blocked claims openly instead of dropping them; the site’s tests reject the phrasings the review would not sign.
InteractionThe First Drop: five bounded steps, keyboard and button driven, with a live announcement for each and no run longer than three seconds.
Art directionKiln dust to storm: a warm serif and a typewriter mono over an authored SVG shower, soil-edge dividers and rubber stamps.
GamePetrichor Garden, a small persistent world where the voice is split: the worm jokes and carries no fact; the readout is dry and official.
The next chapter · whyindex.fyi
The Moon and the rain are the first two studies from The WHY Index: a small publication for the questions that interrupt your day, each answered on its own site, with its evidence in plain sight and its limits said out loud.
Selected work
Correspondence · Open to work
I design and build digital products end to end, and I am taking on new work.
The five case studies above are the evidence. PaperWatcher is a live public service, Proper Till puts a till in any browser, StorageInventory is an open-source Windows tool that inventories a drive and says when it could not see everything, and two evidence-led studies turn small questions into interactive sites with games of their own. PaperWatcher, Proper Till and the two studies each went from problem to working software with one person doing the product thinking, the design and the engineering.
I work best on small, real problems: operational tools, internal systems, products that have to survive daily use by people who did not choose them. Working software arrives early, and progress is reported plainly, including the problems.
What I buildWeb products, operational tools and quiet services, designed and engineered as one piece.
How I workRemotely from Devon, in short iterations, with something running by the end of the first one.
AvailabilityOpen to freelance projects and product roles now.