Rules

THE CABINET — rules

Four cabinets, one square CRT, two balls, two minutes.

The arena is a 100 × 100 box. Each of the four sides belongs to one cabinet. In the middle of your side is your mouth — a gap in the wall. In front of it, 14 units into the arena, is your paddle: a bar that slides left and right along your own side and nothing else. Between them, in the warlords ROM, is your castle: nine bricks across the mouth.

The ball bounces off the solid parts of every wall, off every paddle, and off every brick — chipping the brick away. When a ball crosses your mouth line inside the gap you lose a life and the ball is re-served from the centre. Lose your last life and your mouth is welded shut, your paddle and castle are removed, and the other cabinets fight on in a smaller box. The last cabinet with lives standing wins.

Every deflection speeds the ball up. Where the ball leaves your paddle depends on where on the bar it landed and which way the bar was moving — thirteen outgoing angles, 11.25° apart. That is the whole strategy: a paddle is not only a shield, it is a gun, and every rally is a choice about whom to shoot at.

Seats and sides

num_agents is 4, in every variant and in the certification fixture. One seat = one cabinet = one side of the box.

Seat s drives cabinet perm[s], where perm is a permutation of 0..3 drawn once at t = 0 from config.seed. In-game a cabinet is called by its colour alias and nothing else; real policy names are spectator-side only. perm is written into the replay config JSON and into results.cabinets, and is never visible to any seat. Your +along end touches the next cabinet counter-clockwise: RED → BLUE → GREEN → YELLOW → RED.

The ROM preset table (the rotation)

One engine, three presets, applied defaults → the named preset → any explicitly supplied key.

Everything else — arena size, depths, brick geometry, the speed ramp, the timings, the decision cadence, the wall-clock budget and num_agents — is identical across all three ROMs, which is what makes one score scale and one wall-clock budget correct for all of them.

Geometry and constants (fixed in every ROM and every episode)

ArenaSide         = 1 000 000 µu  (100.00 cu, 1 cu = 10 000 µu)
BallHalf          =    12 000 µu  (  1.20 cu)  -- an axis-aligned square
PaddleDepth       =   140 000 µu  ( 14.00 cu)
PaddleThickHalf   =     8 000 µu  (  0.80 cu)
FarPaddleDepth    =   340 000 µu  ( 34.00 cu)  -- foozpong only
PaddleTravelHalf  =   430 000 µu  ( 43.00 cu)
PaddleStepSpeed   =     4 000 µu/tick (0.40 cu/tick)  -- one drive level
PaddleMaxSpeed    =    16 000 µu/tick (1.60 cu/tick)  -- level 4
BrickRowDepthLo   =    80 000 µu  (  8.00 cu)
BrickRowDepthHi   =   105 000 µu  ( 10.50 cu)
BricksPerRow      = 9             -- centres at along -16, -12, … +16 cu
BrickHalfWidth    =    18 000 µu  (  1.80 cu)  -- 3.60 cu wide, 0.40 cu gaps
BallSpeedStep     =       350 µu/tick per deflection
BallSpeedMax      =    13 000 µu/tick (1.30 cu/tick = 31.2 cu/s)
ServeDelayTicks   = 24            -- 1.0 s of dead air after a concede
HoldTicksMax      = 48            -- 2.0 s, the longest a catch may hold
OutfanAngles      = 13            -- 22.5° … 157.5°, 11.25° apart
maxTicks          = 2880  (120.0 s)   -- 24 decision turns
turnTicks         =  120  (  5.0 s)   -- the decision cadence

PaddleMaxSpeed exceeds BallSpeedMax, so a paddle can always out-run the ball along its own side: a miss is a decision, never a physics limitation.

Resolution order (every tick, no exceptions)

1. Turn boundary. At t mod 120 == 0 the stances collected for this turn become each seat's standing stance and one stance record per seat is written into the replay.
2. Autopilot compile, in cabinet index order, into a command byte cmd ∈ 0 … 242: near = cmd mod 9, far = (cmd div 9) mod 9, grip = cmd div 81, paddle velocity = (level − 4) × PaddleStepSpeed. cmd >= 243 is repaired to 40 in both the server and the replay runtime.
3. Paddle motion, cabinet order, near then far; a paddle that hits its travel limit simply stops.
4. Ball motion and contacts, ball order, at most one contact per ball per tick, earliest first, ties broken paddles → bricks → mouth lines → solid walls.
5. Score, folded into a running total.
6. Hash — one gameHash per tick, the integrity chain the browser checks.
7. End checks: last standing → complete/last_standing; the wall-clock stop → deadline/wall_clock; maxTicks → complete/full_time; an invariant guard → fault/sim_fault.

The deflection fan. In side k's local frame, j = clamp(round(offset × 6 / paddleHalf) + spin, −6, +6) and dl' = 16 − 2j, so dl' is always in 4 … 28: a paddle can never deflect a ball into its own mouth. spin is ±2 above 1.20 cu/tick of bar speed, ±1 above 0.40, else 0. A gripped ball is aimed by the drive level in the byte that releases it (j = near − 4), so the release rides the same recorded byte as everything else.

Scoring

Every term is non-negative, so the minimum score is 0.000 and higher is always better. Conceding is punished by not earning the lives term.

score[k] = 20.00 × livesLeft[k] / startingLives × 3   (60.000 max, ROM-independent)
         + 15.000 if placement == 1                   (the crown)
         +  2.000 × knockouts[k]                      (rival lives you took)
         +  0.500 × chips[k]                          (rival bricks your ball broke)
         +  0.250 × saves[k]                          (balls your paddles deflected)

The lives term is normalised by startingLives, so quadrapong's five lives and warlords' three are worth the same at the top of the scale and a league board that mixes ROMs is still meaningful.

Placement, computed once at game over: a cabinet with lives outranks every cabinet with none; among the living, more lives, then more bricks, then more saves, then the lower cabinet index; among the eliminated, later outTick, then more knockouts, then the lower cabinet index. The index tiebreak makes the chain total, so placements is always a strict permutation of 1..4 and exactly one seat takes the crown.

What the league ranks by: the seat's mean results.scores value across its episodes.

End conditions

A seat that never connects does not end the episode: the lobby budget expires, the no-show is reported to COGAME_PLAYER_FAILURE_URI, and its cabinet plays the bulwark baseline for the whole run.

Out of scope

No Atari emulator, no ROM image, no ALE binding and no PettingZoo dependency: the environment names in the source idea are provenance, not a specification, and every constant here is the cabinet's own. No pixel or RAM observations, no team or cooperative motive, no ball–ball collision, no powerups, no inter-seat communication of any kind, and no fog of war — the cabinet is a CRT and the physics is public. What is hidden is who is playing.