Find a repeating structure at stride 368 in the region after shrub

Range measured: level 0, 16047040..16737344, sampled as the first 65536 bytes. Cross-checked on every level that has the region, each sampled the same way from its own region start. Method: autocorrelation. For each candidate stride, count how often a 4-byte sequence at offset i repeats at i + stride, as a fraction of comparable positions. A random control of the same size measured identically reads flat at 0.0000 for every stride, so the statistic does discriminate. stride 368 0.1110 stride 340 0.0935 strides 337-339 0.026-0.029 background random control 0.0000 Stride 368 is the strongest peak. On level 0, 340 is a secondary peak well clear of the background; the two differ by 28, unexplained. The cross-check is the part that matters: the peak stride was recomputed independently for every level with the region, and all 24 peak at exactly 368. One level's peak could be a property of that level's data; 24 of 24 agreeing is a format invariant. What a 368-byte record is remains unestablished. This is the same position the shrub body was in before differential analysis identified its records, and the same method is the obvious next step -- apply it to the 368 stride rather than continuing to look for headers. Chosen deliberately over the header search: autocorrelation found this in one pass with a control, where four header guesses found nothing. The shrub body only yielded to differential analysis too, and pattern-matching is what produced this session's four retractions.
2026-10-11 03:30:50 +02:00
parent 690092dfb6
commit 21791e8f5f
1 changed files with 33 additions and 0 deletions
@@ -185,3 +185,36 @@ less than a structure needs.
 Recorded because the lead was committed as a lead and this is where it goes.
 Nothing else about the region has been identified: it is real, non-zero data
 of unknown type, bounded, and unopened beyond these ~150 bytes.
 ## The region after shrub has a repeating structure at stride 368
 **Range measured:** level 0, `16047040 .. 16737344`, sampled as the first
 65,536 bytes. Cross-checked on every level that has the region, each sampled
 the same way from its own region start.
 **Method:** autocorrelation. For each candidate stride, count how often a
 4-byte sequence at offset *i* repeats at *i + stride*, as a fraction of
 comparable positions. A random control of the same size is measured
 identically and reads flat at 0.0000 for every stride, so the statistic
 discriminates.
 **Result:**
 | stride | region match rate |
 |---|---|
 | 368 | 0.1110 |
 | 340 | 0.0935 |
 | 337–339 | 0.026–0.029 (background) |
 | random control | 0.0000 |
 Stride **368** is the strongest peak. On level 0, 340 is a secondary peak
 well clear of the background; the two differ by 28, which is unexplained.
 **Cross-check:** the peak stride was recomputed independently for every level
 that has the region, and **all 24 peak at exactly 368**. That is the part
 that makes this worth recording -- a single level's peak could be a property
 of that level's data, but 24 of 24 agreeing is a format invariant.
 What a 368-byte record *is* remains unestablished. This is the same position
 the shrub body was in before differential analysis identified its records,
 and the same method is the obvious next step.