TITLE Aerodrome Lisbeth — Airship Departures PROMPT The main departures board of an invented airship terminal, "Aerodrome Lisbeth, Mast Field East", built as a mechanical split-flap (Solari) display that fills the screen. Concept: a dashboard that is physically believable; every character is a real two-part flap that flips through intermediate characters to reach its target. Palette: board black #0F0F0E, flap face #1A1A18 with a hairline split, character white #F2EFE4, signal yellow #F5C400 for status words and the header rule, alarm red-orange #D4401F for "CANCELLED/STORM HOLD". Dark page. Subtle texture: flaps have a faint top-light gradient, the hinge line casts a thin shadow, the board has a brushed enamel frame with small rivets and a brass maker's plate ("Lisbeth Signalwerk, Type 4"). Typography: flap characters in a condensed bold sans stack ("Arial Narrow", "Helvetica Neue Condensed", Impact-like fallback, squeezed horizontally to fit a flap if the fallback is wide) in caps; header "DEPARTURES · ABFLUG · PARTENZE" in wide-tracked small caps under the station name and a yellow airship pictogram; a large clock built from flaps showing the viewer's actual local time (HH:MM:SS, seconds flip every second) with the local weekday and date beside it. Content: 11 rows (10 on phones, with fewer columns): TIME, DESTINATION, SHIP, MAST, STATUS, plus a small signal lamp per row (blinking yellow while boarding, steady red for holds and cancellations). Invented destinations and ships with a consistent world: e.g. 06:40 SALT MERIDIAN / LZ HALCYON / MAST 3 / BOARDING; CAPE VERRAT; THE UPPER LANTERNS; NEW ODESSA SKYPORT; PORT ISOLDE; statuses: ON TIME, MOORED, GAS CHECK, BALLASTING, BOARDING, DEPARTED, DELAYED, STORM HOLD, CANCELLED. The schedule is derived from the real clock: departures are generated deterministically one to three minutes apart around now; each ship's status steps forward as its real departure time approaches, departed rows expire about half a minute later and the board shifts up, so on average something changes roughly every 20 seconds and whenever a departure time passes. Signature moment: the cascade. When the board updates, every changed cell flips forward through the drum in order (A→B→C…, like a real Solari, ~55ms per flap). Each flap is drawn as a 3D fold: the top half swings down about the hinge, foreshortening and darkening as it turns from the light, and its back face, carrying the lower half of the next character, lands on the bottom half with a small bounce on the final flap. Flips are staggered left-to-right and top-to-bottom so a wave of motion rolls down the board. The flaps are painted on small canvases from pre-rendered sprite sheets so hundreds can turn at once without dropping frames. On load the entire board starts blank and resolves in a roughly 3-second cascade. Optional sound (off by default; a designed toggle shaped like a small brass switch): each flap makes a tiny filtered-noise tick via Web Audio, so a cascade becomes a clatter. Interaction: clicking/tapping a row (or Enter/Space on it) expands a flap-built detail strip under it (captain, expected time, lifting gas, cruise altitude, passengers aboard, and a wry purser's note like "Cabin band: the Ostend Trio"); filter chips ALL / BOARDING / DELAYED, with live counts, re-sort the board with a cascade, bringing matching rows to the top and dimming the rest; pressing R or pulling the brass "Next announcement" lever forces an update (the head row is cleared, everything shifts up and the next announcement begins). Pressing the maker's plate runs a self-test in which every flap makes one full revolution. A scrolling single-line announcement in a yellow 5×7 dot-matrix, stepping one dot column at a time over a lattice of unlit dots, sits at the bottom ("Passengers for Cape Verrat are reminded that kites are not permitted on the promenade deck."). Below the board: a small fictional wind and pressure panel with an animated windsock drawn in SVG, a compass dial, flap readouts and a barograph trace. Phone layout: fewer characters per column, abbreviated destinations and statuses, SHIP column folded into the detail strip. Reduced motion: flaps change with a quick crossfade instead of cycling, the announcement becomes static wrapped text and the windsock holds still. DESCRIPTION A dark terminal hall with one object in it: an enamel-framed Solari board for an airship aerodrome that never existed. The page opens on blank flaps; within three seconds a wave of clattering characters rolls from the top-left to the bottom-right and resolves into a full schedule of airships whose times are anchored to the viewer's own clock. From then on the board lives by itself: the flap clock ticks every second, statuses creep from ON TIME through GAS CHECK and BALLASTING to BOARDING and DEPARTED, rows expire and the whole board shuffles up in another cascade, a yellow dot-matrix notice crawls along the bottom with deadpan announcements, and a windsock below drifts with an invented wind. Brass hardware on the frame (a toggle switch for the clatter, a pull lever, a maker's plate) invites touching, and every row opens into a small flap-built manifest with its captain, gas and a purser's remark. VISUAL TECHNIQUES - Split-flap engine drawn on per-field canvases: pre-rendered sprite sheets for every character, size and colour, with time-based fold animation (foreshortening, widening toward the viewer, darkening front face, lit back face, cast shadow, bounce on the final flap) - Forward-only drum cycling with left-to-right, top-to-bottom stagger to produce the cascade wave - Device-pixel-ratio aware canvases (capped at 2) with dirty-cell redraws only - Flap faces with top-light gradient, hairline split, hinge shadow and side pins painted procedurally - Hand-encoded 5×7 dot-matrix font rendered as glowing dots over an unlit lattice, scrolled in whole-dot steps - Brushed-enamel frame, rivets, brass plate, toggle switch and lever built from layered CSS gradients and shadows - Inline SVG airship pictogram, animated windsock (procedural segmented path), compass dial and barograph - Deterministic hash-based schedule and smooth pseudo-weather computed from the real clock - Web Audio filtered-noise ticks, rate-limited to one burst per frame and scaled by the number of flaps turning - Spring and glide cubic-bezier easings for the switch, lever, chips, compass needle and expanding detail strip - SVG turbulence grain overlay and warm overhead light on the page - Responsive cell sizing computed from the board width, with three column layouts INTERACTION MODEL The board runs on its own from the viewer's local time. Hovering a row brightens its flaps; clicking, tapping or pressing Enter/Space on a row opens a detail strip beneath it whose flaps cascade in with the ship's manifest, and selecting it again closes it. The filter chips ALL, BOARDING and DELAYED re-sort the rows with a cascade, moving matches to the top and dimming the others. Pulling the "Next announcement" lever or pressing R clears the head row, shifts the board up and starts the next notice. The brass toggle turns the flap clatter on or off (sound is off until switched on). Pressing the maker's plate runs a full-revolution self-test of every flap. All controls are keyboard-focusable with visible focus rings and work with touch; with reduced motion enabled, flaps crossfade and the notice is shown as static text.