BB(6) hunt

1RB1RF_1LC0RB_1RD0LC_1LE1RA_0RC1LB_---1RE

Where it stands

Parked at the observation

Parked by Dennis 2026-10-10 (park_sim): niced background sim to 1e12 as a cheap halt check, work/sim_1e12.jsonl. Observe done: period-5 sea with 2-state defect walls forming nested binary counters (7 exact local rules validated on random instances; inner counter laws 33,140/33,140 and 5,545/5,545 on the orbit). Confidence is low because the global law (engine-dissolving epochs, bit creation, edge regions; regime change at ~2.7e9) is unknown, and a halting route (C reading 0 before 110) exists in the defect algebra. Proof work waits for Dennis.

Observe
Deepen
Informal proof
Rocq
space-time diagram, first 10,000 steps from blank
The first 10,000 steps from a blank tape. Time runs down; white is 1.
About this picture

The standard picture (bbchallenge.org's Default view): each row is the whole tape at one step, time runs downward, and the head's path draws the pattern.

bbchallenge-defaultStart blankRows steps 0 → 10,000, top to bottomWindow cells −200..199, left to rightColors 1 0 or unvisited

Overview

In one sentence

Period-5 sea swept by a zig-zag head; defect walls toggle like binary counters; the global epoch law is unknown

Status
Parkedobserving · updated 2026-10-10Not blocking · Stuck at the observing stage. Answer Q1–Q3 whenever; a “no” redirects the work.
idle since Oct 10 13:59 · status.json 2026-10-10
Class
Unknownours: sheet Unknown ≠ ours Nested binary counters of toggling defect walls in a period-5 sea, with engine-dissolving epochs (multi-region) · low confidence
On the list
line 562 of BB6_holdouts_663.txt · historical 740 line 625 · observe.json rank #49
R9eqv ×1sim 1e13
Your calls on file 3
priority call (answered)
One more stage on the epoch/bit-creation law (exact wall catalogue + abstract wall simulator), or park as STUCK at observe?
parked
Parked by Dennis 2026-10-10 (park_sim): niced background sim to 1e12 as a cheap halt check, work/sim_1e12.jsonl.
decision.json · answered 2026-10-10: park_sim
Spend one more stage on the epoch/bit-creation law (wall catalogue plus an abstract wall simulator), or park R9 as STUCK at observe? Decisions →

Mechanism

How it works: 3 notes
  • Sea and walls: the tape is mostly the period-5 sea 11100. Right sweeps (B) shift every block 2 cells right and left sweeps (C) shift it back, 7 steps per block. The head turns only at 2-state defect walls. A right-wall bit is the insert 000 (= 0), which reflects a right sweep and becomes 100 (= 1); 100 lets the sweep through and is reset on the way back. Left-wall bits (gap-1 vs run-2) do the same to left sweeps. So the central engine drives a binary counter on each side (counter laws hold on 33,140/33,140 and 5,545/5,545 orbit turns).
  • Above that it is not understood. Counter overflows feed a second engine/counter pair at the right end and a structure at the left edge. Up to 2.73e9 the inner engine keeps dissolving (43 epochs between 1e9 and 2.73e9, 29e6 to 56e6 steps apart): a wall walks left one block per bounce, eating a 4/5-density sea (11110) back into 11100, and then the engine re-forms. After 2.73e9 there are none in the inner region. Each edge visit adds 3 cells (2,021 cells at 1e10), and edge visits keep slowing down.
  • Halting: every halt is C reading 0 just before 110 (rule H), for example a right sweep meeting B> 1^n 0 1 0, or a D sweep meeting 110. Neither is seen to 1e10. Cryptid check: nothing Collatz-like. Everything observed is binary counting or linear drift, but the unknown epoch/bit-creation law could still hide parity branching.

Figures for Checkpoint A

Fig 1 · Edge records to 10 billion steps

One row per new edge cell. Compare the two edges' slopes, then follow the wavy grey lines inside.

Edge records to 10 billion steps
bbchallenge-defaultStart blankRows the start, then one per new leftmost or rightmost cellWindow cells -729..1291, 1 px = 1 cellColors 1 0 or never visited head at a new right/left edge
Rows: (2,021 rows, steps 0..9,957,807,009); not evenly spaced in time
Fig 2 · Close-up after step 1e9: engine and countersQ1

Time runs down. Note which dark column each right excursion from the engine (x ~ 200) stops at.

Close-up after step 1e9: engine and counters
bbchallenge-defaultStart mid-run: step 1,000,000,000Rows every 8 stepsWindow cells 250..1000, 1 px = 1 cellColors 1 0 head after a right/left move
Start: head at cell 502 in state B moving right · Rows: 2,001 rows (steps 1e9 .. 1e9 + 16,000) · Window: (column x = cell 250 + x); right-counter bits sit at cells 680, 733, 778, 808, 821, 862, 867, 875
Fig 3 · Where the head turns, log time to 1e9Q2

Each line is a wall the head keeps bouncing off. Note where lines are born and which way they drift.

Where the head turns, log time to 1e9
customStart blankRows 800 log-spaced time bins from step 1e3Window cells -549..988, 1 px = 1 cellColors no turn right turning point (R -> L) left turning point (L -> R)
Rows: (top) to 1e9 (bottom); a turning point is a sweep's extreme cell before the head moves 8+ cells back · Colors: dark = both; darker = more turns in the bin (log scale)
More figures (2)Fig 4–5: Blaze view, 1 billion steps · bbchallenge Default view, first 10,000 steps
Fig 4 · Blaze view, 1 billion steps

Time runs down. Edges grow on both sides; the paler vertical bands are defect-rich zones.

Blaze view, 1 billion steps
bbchallenge-blazeStart blankRows Blaze time blocks of 1,048,576 stepsWindow cells -549..988, 1 px = 1 cellColors 0 1 a cell that is 1 for part of its time block
Rows: (954 rows, each averaged), steps 0..1e9
Fig 5 · bbchallenge Default view, first 10,000 steps

For orientation: what bbchallenge.org shows for this machine.

bbchallenge Default view, first 10,000 steps
bbchallenge-defaultStart blankRows 10,000 steps squeezed into 500 px rowsWindow cells -200..199, 1 px = 1 cellColors 1 0 or never visited head after a right/left move
Rows: 1 px row = 20 steps; the site blends steps 20y+9 and 20y+10
Rules (10/11 validated)exact tape rewrites the proof will formalize, each re-checked by simulation
rulefrom ⟶ tocasesstepschecked
S_R right sweep over the sea
B> (11100)n
⟶ (00111)n B>
any n >= 1, random 12-cell contexts on both sides7n✓200/200
S_L left sweep over the sea
(00111)n <C
⟶ <C (11100)n
any n >= 1, any context7n✓200/200
RB0 right bit 0 reflects, becomes 1
(00111)n B> 000
⟶ <C (11100)n 100
n >= 1; the turn and the start of the return sweep7n+1✓200/200
RB1 right bit 1 passes the sweep
B> 100
⟶ 111 B>
any context5✓200/200
RB1r return sweep resets a passed bit
(00111)n 111 <C
⟶ <C (11100)n 000
n >= 1; together RB1 then RB1r take bit 1 -> 07n+3✓200/200
LB0 left bit 0 (gap 1) reflects, becomes run 2
00011 10111 (00111)n <C
⟶ 00011 00111 (00111)n B>
n >= 1, constructed context. The pass-through case (left bit 1) depends on the phase of the sea on its right and is not yet an exact rule14n+13✓200/200
D_R D sweep: 3/5 sea -> 4/5 sea
D> (11100)n
⟶ (11101)n D>
any n >= 1. A block 110.. instead of 111.. makes F read 0, which halts5n✓200/200
H the only way to halt
0 <C 110 or C> 0110
⟶ halt
C0, D1, A1, then F reads 0. F is entered only by A1, A only by D1 and D only by C0, so every halt has this form (200 random contexts per direction)4✓400/400
CR inner right counter = binary +1
bits b0..b7 = inserts 000 (0) / 100 (1) in the 11100 sea (cells 680..875 at 1e9); a right sweep leaves the engine
⟶ turns at the first 0 bit j; bits < j become 0 and bit j becomes 1
real orbit, steps 1e9..1.03e9: every right turn in cells 600..900 after a left turn left of cell 600; 33,139/33,139 next states are exact +1. Depth counts 16,634 / 8,318 / 4,158 / 2,080 / 1,040 / 520 / 260 / 130—✓33140/33140
CL inner left counter = binary +1
4 low bits in cells 315..435: run-2 defect (1) / gap-1 defect 3 cells right (0)
⟶ turns at the first 0 bit; lower bits -> 0, that bit -> 1
real orbit, steps 1e9..1.01e9, every left turn after a right turn right of the zone; 5,371/5,371 exact +1; 346 carries past bit 3—✓5545/5545
EP engine-dissolving epochs (open)
inner engine + counters
⟶ the engine dissolves; a wall walks left 5 cells per bounce, eating the 11110 sea; the engine re-forms further left
Wall-walk detector (8+ left turns in a row, each 5 cells left of the last): 136 runs from 5e5 to 2.73e9. Between 1e9 and 2.73e9 they form 43 epochs, 2.9e7 to 5.6e7 steps apart. 5 runs near the right end (3.7e9..4.6e9), none after that to 1e10. No exact rule yet—–untested
Compressed historythe tape as span lo..hi of the visited tape; drift = wall-walk runs so far (8+ left turns in a row, each 5 cells left of the last; one epoch can give 2-3 runs) at 15 moments: where the rules are read off
span lo..hi of the visited tape; drift = wall-walk runs so far (8+ left turns in a row, each 5 cells left of the last; one epoch can give 2-3 runs)
steplohicellsdrift
1,000-1228410
3,000-1537530
10,000-2161830
30,000-30701010
100,000-511181700
300,000-811752570
1,000,000-1232563802
3,000,000-1773615392
10,000,000-2855298159
30,000,000-3817151,0979
100,000,000-4327961,2299
300,000,000-4658441,31013
1,000,000,000-5499881,53830
3,000,000,000-6841,2161,901136
10,000,000,000-7291,2912,021141
lolast -729
-12-7291,0001e10log xstep 1000: lo = 12step 3000: lo = 15step 10000: lo = 21step 30000: lo = 30step 100000: lo = 51step 300000: lo = 81step 1000000: lo = 123step 3000000: lo = 177step 10000000: lo = 285step 30000000: lo = 381step 100000000: lo = 432step 300000000: lo = 465step 1000000000: lo = 549step 3000000000: lo = 684step 10000000000: lo = 729
hilast 1,291
1,291281,0001e10log xstep 1000: hi = 28step 3000: hi = 37step 10000: hi = 61step 30000: hi = 70step 100000: hi = 118step 300000: hi = 175step 1000000: hi = 256step 3000000: hi = 361step 10000000: hi = 529step 30000000: hi = 715step 100000000: hi = 796step 300000000: hi = 844step 1000000000: hi = 988step 3000000000: hi = 1216step 10000000000: hi = 1291
cellslast 2,021
2,021411,0001e10log xstep 1000: cells = 41step 3000: cells = 53step 10000: cells = 83step 30000: cells = 101step 100000: cells = 170step 300000: cells = 257step 1000000: cells = 380step 3000000: cells = 539step 10000000: cells = 815step 30000000: cells = 1097step 100000000: cells = 1229step 300000000: cells = 1310step 1000000000: cells = 1538step 3000000000: cells = 1901step 10000000000: cells = 2021
driftlast 141
14101,0001e10log xstep 1000: drift = 0step 3000: drift = 0step 10000: drift = 0step 30000: drift = 0step 100000: drift = 0step 300000: drift = 0step 1000000: drift = 2step 3000000: drift = 2step 10000000: drift = 9step 30000000: drift = 9step 100000000: drift = 9step 300000000: drift = 13step 1000000000: drift = 30step 3000000000: drift = 136step 10000000000: drift = 141
Template comparisonCPS_LRU_v3.v: does not apply · the nearest solved proof, what carries over, and the transitions that differ
01
A1RB1RFtpl 0RF
B1LC0RB
C1RD0LC
D1LE1RA
E0RC1LB
F---1REtpl 0LE

differs from the template

file
CPS_LRU_v3.v:2133
module
—
machine
1RB0RF_1LC0RB_1RD0LC_1LE1RA_0RC1LB_---0LE (2 transitions apart)
diff
A1 1RF->0RF, F1 1RE->0LE
note
Nearest proved machines by table (2 cells away): a CPS_LRU_v3 certificate (this one; it stops growing at 124 cells by 1e8), CPS_LRU_v4 and RWL_mod_v1. All three are decider certificates, not structural proofs. The targeting row's verify/CounterCmp_v1.v (TM1) compares two unary counters, which is a different mechanism. Kill #12's recursive run-length counter is the closest kill in spirit, but its tape is runs of 1s, not a period-5 sea with toggling walls. No template applies.
Proof strategy & riskshow the formal proof will go · 3 risks to watch

Not ready for a proof. Next: (1) an exact catalogue of every wall shape in both sea phases; (2) an abstract walls-and-counters simulator checked against the TM to 1e10; (3) the epoch and bit-creation law, plus an invariant that rules out C reading 0 before 110 (B> 1^n 0 1 0, D> 110).

  • ▲Several levels: two engine/counter pairs, edge structures and engine-dissolving epochs; the regime changed at ~2.7e9, so 1e10 steps may not show every regime.
  • ▲The defect algebra has real halting routes (B> 1^n 0 1 0, D> 110), so non-halting needs a global invariant on defect shapes, not just the counter laws.
  • ▲Nobody has simulated it to 1e14 (sheet). qsim does not accelerate it (block size 1, 0 rules by 5.4e6 steps), and direct simulation of the growing gaps between edge visits is slow.
Stats & provenance1010 steps simulated · 2,021 cells · the status in full · files
simulated
1010 steps
tape
2,021 cells · 1,224 nonzeros
growth
+3 cells per edge visit; visits slow down (left edge about every 4e7 steps near 1.5e9, about every 1.5e9 near 8e9); 1,538 cells at 1e9
status now
Parked by Dennis 2026-10-10 (park_sim): niced background sim to 1e12 as a cheap halt check, work/sim_1e12.jsonl. Observe done: period-5 sea with 2-state defect walls forming nested binary counters (7 exact local rules validated on random instances; inner counter laws 33,140/33,140 and 5,545/5,545 on the orbit). Confidence is low because the global law (engine-dissolving epochs, bit creation, edge regions; regime change at ~2.7e9) is unknown, and a halting route (C reading 0 before 110) exists in the defect algebra. Proof work waits for Dennis. (status.json, 2026-10-10)
observer's note
Observe done. Low confidence: the sea sweeps, wall toggles and both inner counter laws are validated, but the global epoch/bit-creation law is not, so proof work waits for Dennis.
files
observe.json · notes.md · status.json

Proof & checks

No proof work yet.

Files

machines/<tm>/: 6 entries · raw notes, status, scripts, images

namesizechanged
notes.md ↓7.4 KB2026-10-10 13:59
status.json ↓967 B2026-10-10 12:52
observe.json ↓13 KB2026-10-10 11:03
decision.json ↓3.6 KB2026-10-10 12:49
img/5 items2026-10-10 10:59
work/11 items2026-10-10 12:49
status.json in full
{
 "tm": "1RB1RF_1LC0RB_1RD0LC_1LE1RA_0RC1LB_---1RE",
 "status": "STUCK",
 "stage": "observe",
 "updated": "2026-10-10",
 "reason": "Parked by Dennis 2026-10-10 (park_sim): niced background sim to 1e12 as a cheap halt check, work/sim_1e12.jsonl. Observe done: period-5 sea with 2-state defect walls forming nested binary counters (7 exact local rules validated on random instances; inner counter laws 33,140/33,140 and 5,545/5,545 on the orbit). Confidence is low because the global law (engine-dissolving epochs, bit creation, edge regions; regime change at ~2.7e9) is unknown, and a halting route (C reading 0 before 110) exists in the defect algebra. Proof work waits for Dennis.",
 "parked": "Parked by Dennis 2026-10-10 (park_sim): niced background sim to 1e12 as a cheap halt check, work/sim_1e12.jsonl.",
 "priority_call_answered": "One more stage on the epoch/bit-creation law (exact wall catalogue + abstract wall simulator), or park as STUCK at observe?"
}