Opus 5.5 built an 8-slide watch explainer where every mechanism actually moves

An 8-slide animated deck on how a mechanical watch keeps time: mainspring, gear train, escapement, balance wheel, the hands, winding, then the whole movement running together. Every drawing is SVG driven by one shared clock, so meshing gears keep their ratios and the escape wheel only steps when the pallet fork flips. It's a single HTML file of about 40 KB, arrow keys to move. How it was made: Opus 5.5 in Claude Code, running the slide workflow from SenseNova-Skills (MIT). My brief was the eight slide topics, at most 35 words per slide, no photos or outside assets, and no specific figures like beat rates. The skill has it write an outline and a design plan, then build each slide, render it and look at the image before moving on. Every slide got at least two looks, and it fixed a drawing that spilled outside the watch case and labels that ran into parts or sat too close to the edge. The escapement is drawn in a simplified way. The whole build took 26 minutes. The video is the deck playing through in a browser, about 6 seconds a slide.