A dot grid backdrop driven by a real spring, not a lerp. Dots carry velocity, so they get flung past their rest position and ring back — and the field reads how fast you move, not just where you are: a swipe throws dots further than the same path taken slowly. Click for an expanding shockwave. The canvas is pointer-transparent and listeners bind to the container, so it keeps reacting under headlines and buttons. Fixed 1/120s sub-stepping keeps the spring stable and frame-rate independent; the dirty rect bounds the cost to the influence radius.

An isometric slab field where every slab's height tracks pointer proximity and springs independently. The pointer flows through a motion value into each slab's path `d` string at 60fps — no React state, no re-renders while it moves. Pointer events, so it works under touch and pen, not just a mouse.

An infinite strip whose speed and skew couple to scroll velocity — it accelerates as you scroll, reverses when you scroll back, and eases to a base drift when you stop. The wrap is a modulo on a measured content width (seamless in both directions, no CSS-animation restart), and the velocity is smoothed by an exponential moving average so it coasts instead of snapping.

Per-glyph variable-font response to pointer proximity — axes swell near the cursor and relax away from it, continuously and reversibly. Glyph boxes are pinned to their resting widths so animating `wght` can't shift neighbours, stale the cached centres, or re-wrap the line; centres are measured once and only re-read on resize or font swap. The accessibility tree reads one clean string.

True SVG path interpolation between two icons — not a cross-fade. Ships its own path normalizer with no dependency: a cursor-based parser (correct on packed arc flags, where a number regex silently fails), every command reduced to cubics including the full endpoint→centre arc conversion, equal-arc-length resampling, and a rotation/direction search that minimises total travel so the morph never ties itself in a knot. Multiple subpaths are paired by centroid, and an unmatched one collapses into its nearest counterpart.

Continuous scroll-linked animation on the native Scroll-Driven Animations API, with a JS fallback that is numerically identical rather than merely similar. Both paths drive one registered custom property, `--st-progress`, so there is a single renderer and only the source of the number changes — the spec's four view-progress ranges and a real cubic-bézier solver make the fallback match to ~1e-6. Set `forceFallback` on one of two instances to check it yourself.

A canvas dot grid that reacts around the cursor, at a density SVG can't reach. The per-frame cost is bounded by the influence radius rather than the dot count: only the dirty rect is cleared and redrawn, and dots are batched into 16 paths by quantised alpha instead of one fill each. DPR-correct on retina, and the rAF loop is genuinely cancelled — offscreen, backgrounded, or simply settled.

Drag-to-reorder, hand-written, with a keyboard mode that shares the same code path. The target index is a pure function of geometry frozen at lift and the pointer delta — monotonic in the delta by construction, so there is no feedback loop to oscillate in at any drag speed. Pointer capture, edge auto-scroll, a drop animation into the final slot, and `aria-live` announcements throughout.

A bottom sheet with snap points that feels native rather than like a `<div>` with a transition — three formulas and a state machine. Snapping is velocity-projected, so a flick and a slow drag past the same point resolve differently; bounds use Apple's rubber-band curve; and the drag-vs-scroll decision is made on the first `pointermove` past a 4px threshold and locked for the whole gesture, which is what stops a sheet from stealing a scroll halfway through.

Reveals its children with a soft de-blur + fade as they scroll into view — the 'text develops into focus' effect. Fires once, respects reduced-motion, and is polymorphic via `as` so it can wrap a heading, paragraph, or a single list item.