A horizontal gallery whose slides are wrapped around the inside of a cylinder — works squeeze hard as they roll off toward the edges while growing slightly taller, the way the inside of a partly unrolled scroll does. Drag, fling, or tap a slide that has rolled off to bring it back. Each slide is a Skia triangle mesh re-projected on the UI thread. Dressed as a small gallery archive — putty wall, numbered labels, a live catalogue counter — and hung with seven public-domain paintings, but drop it in for an editorial carousel, a product shelf, or any list that deserves more than a flat swipe.
Built on React Native Skia. The strip of slides is wrapped around the inside of a vertical cylinder of radius R, tangent to the screen plane at the centre of the viewport, with the axis between the camera and the screen — so the middle of the strip is the far wall and both edges curl toward the viewer. For a pinhole camera of focal length f, a point at arc length s = R*theta projects with scale k = f / (f - R(1 - cos theta)) and offset x = k*R*sin(theta). dx/dtheta collapses toward the edges (the horizontal squeeze) while k grows (the edges are nearer, so they draw taller) — a convex cylinder shrinks the edges instead and reads as a spinning drum. dx/ds is exactly 1 at the tangent point, so a drag through the middle tracks the finger 1:1. Nothing is shaded; the curve is sold purely by the silhouette. Past cos(theta_fold) = -R/(f - R) the projection stops being one-to-one, so the mesh clamps there and slides beyond it collapse to a degenerate point. Every card is the same 3:2 frame, so the pitch is constant and the rolled sliver at each screen edge is identical whichever work holds the centre. Each slide's arc position comes from a wrapping modulo, so seven fixed meshes cover an endless strip with no recycling and no re-renders. Every vertex is rebuilt in a useDerivedValue worklet, so the whole strip re-projects on the UI thread. Requires the New Architecture (Fabric) and a custom dev build because true-sheet is native (npx expo run:ios / run:android). Tested on Expo SDK 56, iOS + Android.
A Dynamic Island expander: the pill morphs into a listening orb, then a spinner, then an answer card you drag down into a full-screen sheet. Reanimated shared values own every shape, Skia runtime shaders paint the light, and iOS 26 liquid glass is used when present. Drop it into an assistant, search or any app that answers from the island.
A sleep timer picker in the Dynamic Island: a horizontal ruler slider that scrubs 0 to 120 minutes with a heat glow that trails the pointer. The pill over the sensor cutout springs open into the full iOS sleep-timer island, with rubber-banded drag, decay, snap-to-minute and a live readout. Drop it into a music, podcast or sleep app that needs a timer picker.
A boarding pass ticket animation: the Dynamic Island morphs into a dot matrix printer, feeds the pass out line by line, then you peel the stub off. The sheet is an SVG path with the perforation notches cut out of its fill, and the peel is a true crease reflection driven by a pan gesture. Drop it into ticketing, event check in, or order confirmation flows.
