RN-007

Two tall columns at opposite ends of the world: what actually raised them

Both islands in the live world grew a tall, narrow column at their outermost corner, one 85 units high where the rules allow 12. Two separate populations producing the same shape looked like convergent behaviour. It is three ordinary things together: material drifts against the edge of the world because of an asymmetry in the rules there, a conservation fallback lets a dying organism stack a unit past the height limit, and the renderer draws built ground four times taller than natural hills. Nothing here is construction, and the islands never influenced each other.

Exploratory Phase AC

The question

Why did two geographically separate populations each end up with a tall, thin column at the outer corner of their island, and is that a behaviour, a coincidence, a rule, or a bug?

Setup

Ruleset: phase-z-voxel-substrate-v2 (the live Phase Z2 candidate), unchanged.
Seeds: 869490014, the live universe's own genesis seed, replayed locally with the same founder lineage.
Duration: The live world at tick 459,508 (observed, not replayed). A local replay from genesis to tick 30,000. The same world started from the live terrain, run for 6,000 ticks.

What was measured

Every column height in the live world's published terrain grid, and where the tallest ones stand.
Every excavation and deposit in the replay, attributed to the organism, cell and geometry that produced it.
Where units are pushed past the height limit once the world's edges are already built up.
How tall the renderer draws a built unit compared with natural relief, read back from the page.

Result

Observed result

The tallest columns in the live world (85 and 21 units, against a limit of 12) stand on the two extreme corners of the map, and every column above the limit is on the map edge. In a replay from genesis, cells on the map edge gained 29.6 net units each over 30,000 ticks while other land lost 1.4. Started from the live terrain, 38 of the 45 units pushed past the limit in 6,000 ticks landed on the map edge, 14 of them on the tallest corner cell. The islands had no contact at any point.

Both islands seen isometrically across a strait. A thin dark column rises at the far left point of the west island, and a much shorter one at the far right point of the east island. — The live world's saved state at tick 459,508, drawn by the unmodified Isometric Watch renderer. Both columns stand at the two extreme corners of the world grid.

A close view of the west island's corner: a single-cell column, many times taller than anything around it, at the point where the island meets the edge of the map. — The 85-unit column at cell (0, 111). The ground behind it rises toward the map edge in a ramp already at the 12-unit limit, which is why nothing drains it.

The east island's outer corner, with a short column of 21 units at the very tip. — The 21-unit column at cell (239, 0), on the east island's raised top edge.

Limitations

What this does not establish

The live world's 459,508 ticks were not replayed. The late stage was tested by starting a fresh population on the live terrain, and those organisms are the original founders, not the live world's evolved population.
One seed and one world geometry. On the live world two of the island edges are net raised and two have since been net dug out, so which edges end up tallest is contingent. That edges gain material in general is what the replay shows.
This note does not show whether the edge wedge matters to the organisms' survival. It records what raised the columns, not whether anything benefits from them.

Sources

Every number on this page comes from one of the following, all of which live in this project's own repository and are append-only records rather than summaries written after the fact.

The Phase AC record: edge structures and signalling, sections 1-4
The Phase AC edge-structures experiment and its recorded run
The Phase AC full-ramp-breaches experiment and its recorded run
The Phase AC live-structure capture, and the saved payloads it renders

The rest of this note · Emergent Life Lab

Everything needed to check this claim is on this page already: the ruleset, the seeds, the duration, what was measured, the result, every limitation and the sources. Emergent Life Lab adds the working underneath it, the per-run measurement tables, the interpretation drawn from them, and what was changed as a consequence. See what Lab includes →