web development

demo.grn.dk is where the experiments live: twenty-five of them, from an XHTML-era sunrise calculator for Silkeborg to procedural WebGL, a Blender orrery, a crystal hall, an AI receptionist, a UK accounting autopilot and a Danish ERP day. Many of the cases on this page open on a shelf entry. The shelf itself is one PHP file that lists the demos, groups them into Featured and Tools, filters as you type and derives the sitemap from the same list — so a demo that lands in the web root is on the shelf and in the sitemap before anyone writes it up.

flutter.grn.dk is a shelf of thirty small case studies, one per Flutter package worth knowing — routing, state management, animation, charts, maps, storage, i18n — and each one is a live demo the visitor can poke at, with the code beside it and real apps that use the package. There are no screenshots of Flutter on it: the site is itself the Flutter app, compiled for the web, with a real URL per case, a crawlable page behind each URL and a 3D “case park” where every case has its own stand.

A Danish coworking space wanted members to book a table by the hour and pay for it — because at 20 kr. per hour per table, a booking that has not been paid for is not a booking. tableflow.grn.dk is that system, built from the client's brief and running live: an hour grid that shows what is actually free, a fifteen-minute payment hold that releases itself, and an admin screen for the people who run the place. Plain PHP and MariaDB — no framework, no dependencies, 853 lines in seven files.