# C904 — Connect the complete festival walks to the49/70 interface

## Question

Which scaled prefix durations belong to the shared490 measure?

## Inputs

```json
{
  "scale": 7,
  "grids": [
    49,
    70,
    490
  ]
}
```

## Sources

```json
[
  "C839–841",
  "C869"
]
```

## Opened utc

2026-09-28T02:55:09.518686+00:00

## Results

```json
{
  "classification": {
    "path": "model/festival_common_measure.json",
    "sha256": "bb2701e6a04d267a6ee3826881a79e4dfdb4e929f7bbbc3016d8fb69ac02b0f9",
    "bytes": 2156
  },
  "shared490": {
    "forward": [
      0,
      140
    ],
    "reverse": [
      0,
      140
    ]
  }
}
```

## Finding

For countc,7c lies in49Z,70Z or490Z exactly when7,10 or70 dividesc. Both complete walks meet the common490 grid only at count0 and140. Their other shared prefixes59 and199 are outside it. Equal duration membership does not identify events across anchors.

## Reassessment

Extend the insertion comparison across the source-specific Cainan measurements.

## Checks

```json
{
  "full18": true,
  "common": true,
  "duration980": true,
  "limits": true
}
```

## Closed utc

2026-09-28T02:55:09.519282+00:00

## Record provenance

Exact record hash: `d922f887fa03efb19b3bdea07e128c10a2b621f767d0e11a50fed39f6c29a03b`

Source journal: `Research_Cycles/C0832_C0931/journal.json`