A personal blog by Allen: the apps I make, the piano I practice, the anime I watch, and a fantasy world I'm building.https://practicaltrivia.com/enhttps://practicaltrivia.com/blog/what-if-magic-existed-at-the-dawn-of-humanity/https://practicaltrivia.com/blog/what-if-magic-existed-at-the-dawn-of-humanity/If magic had been part of being human from the very start, what would the world look like? Chapter one of my fantasy world: why the first magic was fire.Mon, 09 Nov 2026 04:40:00 GMTworldbuildinghttps://practicaltrivia.com/blog/javascript-metronome-settimeout-audio-clock/https://practicaltrivia.com/blog/javascript-metronome-settimeout-audio-clock/My app's metronome stuttered on a real iPhone. Why a setTimeout metronome can't keep a beat, how booking clicks on the Web Audio clock fixed it, and code to hear it.Mon, 09 Nov 2026 03:03:00 GMTdevhttps://practicaltrivia.com/blog/wink-page-turn-arkit-mediapipe-face-gestures/https://practicaltrivia.com/blog/wink-page-turn-arkit-mediapipe-face-gestures/How my score app tells a wink from a blink to turn sheet music pages hands-free, with ARKit on iPad and MediaPipe on Android, plus a webcam demo you can run.Mon, 09 Nov 2026 03:02:00 GMTdevhttps://practicaltrivia.com/blog/chord-detection-from-audio-failed-feature/https://practicaltrivia.com/blog/chord-detection-from-audio-failed-feature/I built chord detection from audio for my music app in a day. It passed every test on synthesized songs and failed on real ones. What I built, and code that shows why.Mon, 09 Nov 2026 03:01:00 GMTdevhttps://practicaltrivia.com/blog/adb-emulator-5562-offline-ntkdaemon/https://practicaltrivia.com/blog/adb-emulator-5562-offline-ntkdaemon/expo start failed on an emulator-5562 I never started. The cause was Native Instruments' NTKDaemon on port 5563. How to find what's on the port, and the adb fix.Mon, 09 Nov 2026 03:00:00 GMTdevhttps://practicaltrivia.com/blog/frieren-elves-love-and-the-giant-camp-pot/https://practicaltrivia.com/blog/frieren-elves-love-and-the-giant-camp-pot/Rewatching Frieren, I wondered how elves fall in love and have children when they lack romantic feelings, and where the party keeps that giant pot.Sun, 08 Nov 2026 00:00:00 GMTanimehttps://practicaltrivia.com/blog/piano-practice-ipad-score-app-auto-page-turner/https://practicaltrivia.com/blog/piano-practice-ipad-score-app-auto-page-turner/Practicing piano with MusicTools, the iPad score app I make: a scanned lesson book, half-page turns, page turns with my lips, recording and PDF sharing.Sun, 08 Nov 2026 00:00:00 GMTpianoapps