Six rounds against the wheelie

The pipeline ran its now-standard opening: Physics R&D (Opus) producing a rigid-body reference — a sprung two-wheel chassis on heightfield terrain, in game-feel units chosen to be fun rather than strictly real — while the Audio department (Sonnet) built the collection's first continuous sound: an engine drone that tracks the throttle sixty times a second, ramped smoothly so it never clicks. The Studio Head wrote the whole game around a stub, as usual.

R&D's reference immediately exposed a real bug in the first draft: grip was modeled as drag on the bike's whole velocity — which means the wheels can't roll. They'd brake themselves to a crawl. The fix was spin-based traction: track each wheel's angular velocity and let friction oppose slip, the difference between tire surface speed and ground speed. A freely spinning wheel matches the ground and rolls without loss. With drive torque then rescaled to actually reach the traction cap, top speed quadrupled.

Then came the wheelie — six iterations of public physics education:

1. Stiff dual-wheel contacts self-leveled so hard no torque could lift the nose.
2. Softening the self-leveling made the bike tippy and worse on hills.
3. Heavy pitch damping killed the wheelie entirely.
4. "Unload the front wheel on lean-back" was exactly backwards — the front contact force is itself nose-up, so removing it dropped the nose.
5. The realization, verbatim from the build log: "I'm fighting coupled global constants, which is a losing game… a wheelie is a rider weight-shift."
6. The mechanism that shipped: keep strong self-leveling in neutral — stable on any terrain — and while leaning back, soften the pitch-restoring torque so the nose rises into a controllable balance. Release, and the bike settles back down.

Final numbers: lean back and the front pops to 54° in half a second; hold it too long and you loop out, which is correct — real wheelies are feathered, not held. Backflips work at 4.26 radians of air rotation. And the last "physics bug" wasn't physics at all: the demo tracks were too punishing at full blind throttle. That's level design. The tracks got gentler; all three became beatable at sensible play — Rolling Hills in 4.6 seconds, Whoops in 4.1, Big Air landing its jump at 3.5.

The editor — the other half of the prompt — passed QA in one round: drag terrain points, place start and finish, save to localStorage, round-trip JSON export and import, test and hop back to play. It's the same heightfield the physics runs on, so anything you can draw, the bike can attempt. Whether it should is your problem.

Built 2026-07-18: one prompt, two departments, six wheelie attempts, one reframe — and the lesson that the last bug is sometimes the level, not the engine.