ciechanow.ski: Interactive Physics You Actually Turn, Wind, and Peel Apart

September 2026

$Line illustration of an exposed mechanical watch movement with its case peeled back, showing the gear train, escapement wheel, and coiled mainspring highlighted in rust red against the visible case and wristband.$

Original post: @heynavtoor on X, 2026-09-05. If the embed above doesn’t load, the site itself is linked below and every specific claim in the post is checked against it, not just repeated.

What’s actually on the site

ciechanow.ski is Bartosz Ciechanowski’s own site, and its archive page confirms the post’s claims directly: Moon and tides (2024), Airfoil (2024), Bicycle (2023), Sound (2022), Mechanical Watch (2022), GPS (2022), Naval Architecture (2021), Internal Combustion Engine (2021), Cameras and Lenses (2020), and Gears (2020). Further back, the 2014 posts are iOS-development-specific, which matches the “ex-iOS engineer” background the post describes. He publishes a handful of pieces a year, and some years none at all, matching the post’s “only a few per year, alone, as a hobby.”

Why “interactive” isn’t marketing copy here

Open the Mechanical Watch article to see what the claim means in practice. Drag the watch and it spins in 3D. Pull a slider and the case peels back. Wind the mainspring and watch the escapement click and the balance wheel breathe. Every one of those actions runs as a live simulation in the browser, clearing a genuinely higher bar than the animated-GIF version of “interactive” most explainers settle for.

Why this belongs here

This is the kind of teaching this section exists to collect: real explanation over notation, free of ads or a paywall. Two of his topics sit close to PBT’s own subject matter without touching it directly. His GPS piece walks through the actual relativistic time corrections satellites need, and his Moon piece covers tides, both settled physics explained from first principles rather than assumed. That’s the same job this site tries to do for gravity’s own mechanism: explain the machinery underneath an already-verified result.