the subway knows uptown from downtown. every train now wears a small arrow — up for uptown (northbound), down for downtown — and all 496 stations sit on their lines as pale dots that grow as you zoom in; hover a dot for the station's name.

the subway, three times fresher. train positions now refresh every 5 seconds instead of 15 — the page polls faster and the network holds each answer for a third as long, so a train on the map runs at most ~10 seconds behind the mta's feed instead of ~30.

the subway answers without the slash. chall.net/subway (no trailing slash) served the page but its scripts resolved against the site root and 404'd — black screen, no map. asset paths are now absolute; both spellings of the address work.

THE SUBWAY — every train, live. a live map of the nyc subway at /subway: every train in the system placed on the city in real time from the mta's gtfs-realtime feeds, refreshed every 15 seconds. a hand-rolled zero-dependency protobuf decoder in a vercel function (verified byte-exact against the reference library on all 8 feeds), each train interpolated between its last and next station along official track geometry, official line colors, hover a train for its direction, next stop and eta. adversarial review before ship killed the 3am phantom-train bug (38% of the overnight map was trains that hadn't left the yard) and the daily trip-id ghost collision.

THE SALON — a rotating hanging of the public domain. a screensaver of masterpieces at salon.chall.net: 263 public-domain works from the open collections of eleven museums, hung in gold gilded frames on a wall that follows the sun — paper by day, near-black after dark. one work at a time or a wall of three; ten rooms, from vermeer's delft to hokusai's wave, a storm room, jamaica 1778–1890, and hammershøi's quiet copenhagen. brass-plate captions, a seeded daily hanging, keeps working offline once visited. every image verified against its museum's own open-access api at bake time; no keys, no tracking, one self-contained file.

THE DRIFT — sumi performs itself. press A (or the dock's drift, or arrive via ?drift) and a conductor composes the instrument's own gestures — ring blooms, brush script, comb rakes, fan sweeps, rain — through a programmed hand riding the same stroke physics as yours. it dwells about a minute in each water, then dissolves to the next; every scene visits before any repeats, and light-to-dark crossings take a slow three-second door. while drifting the bath is stiller so inks hold and each scene ends developed. touch the water and the drift ends: the brush is yours.

sumi speaks english, answers only the hand. all chrome in english (no more kanji), and the water only moves when you click and drag — hovering leaves it perfectly still.

SUMI — the floating world. a dedicated suminagashi instrument at sumi.chall.net: seven waters, real marbling tools including the comb, ink wells with a color picker, pulled prints, seeded shareable pours, 120fps on apple silicon. one self-contained file.