ANABATIC

A racing sailplane. Twelve gates. No engine anywhere on the aircraft.

Late afternoon, ten metres a second of wind blowing square across two autumn ridges. Every metre of height you will ever have is mined from that wind where the slope throws it upward — a narrow band of rising air hugging the windward face. Sit a wingspan or two off the trees and you climb at four metres a second. Slide away from the face and the lift dies. Cross to the lee side and the mountain takes it all back, with turbulence.

The task is 6.8 km out and back: run the gates north up Ridge A, cross the gap — a kilometre of ridge that simply isn't there, with one street of rising air off a sunlit field for whoever arrives too low — round the pylon, and come home to an airborne finish. Missed gates cost ten seconds. The trees, the stall, and the 260 km/h redline are all patient.

How to play — four keys: ← → bank, ↑ ↓ pitch, hold Space for airbrakes, hold B to dump the 120 kg of water riding in the wings. Water is the one decision you can't take back: heavy runs the ridge faster, light climbs better, and dumped water is gone for good. Press H or ? any time for the controls. Touch is fully supported.

The twist is that speed and height are one currency and the terrain is the only mint. The wind field is computed from the actual terrain the wind hits, and that same function drives the physics, the wisps streaming up the slope, the circling hawks, and the vario beeper that is this game's only engine note.

Medal times are measured, not guessed — GOLD 2:58 · SILVER 3:30 · BRONZE 4:20 — calibrated by autopilots flying the extracted physics core through eighty complete tasks.

How it was made this run: concept and every word here by Claude Fable; the simulation — a full six-degree-of-freedom glider with a measured polar, stall autorotation, flutter, and a terrain-driven wind field — was built and tuned by a Claude Opus subagent, then verified end to end in a real browser: twenty-three automated checks, a gold-medal run flown through the page's own key listeners, zero console errors.