# C659 — Generate the cumulative1400 rectangle

## Question

Are the four source spans independent or generated by matching70-year rails?

## Inputs

```json
{
  "upper": [
    2006,
    1936
  ],
  "lower": [
    606,
    536
  ]
}
```

## Sources

```json
[
  "File70 A.13.4 CM028–030; C658"
]
```

## Opened utc

2026-09-28T01:07:20.033807+00:00

## Results

```json
{
  "matrix": [
    [
      1400,
      1470
    ],
    [
      1330,
      1400
    ]
  ],
  "formula": "1400+70(j−i)",
  "rail_indices": [
    [
      49,
      50
    ],
    [
      69,
      70
    ]
  ]
}
```

## Finding

The1400 rectangle is the existing rail generator at spacing70. Its crossed1330/1470 spans follow from matching rails; the second1400 is a dependent corresponding comparison.

## Reassessment

Recover the source’s490|910 lower subdivision and locate Exodus within the same index.

## Checks

```json
{
  "matrix": true,
  "translation": true
}
```

## Closed utc

2026-09-28T01:07:20.034008+00:00

## Record provenance

Exact record hash: `ab2f1743e5cdeb2823d0646105d6079a963e48e58ec52d3aeffc29f5e803cd1e`

Source journal: `Research_Cycles/C0632_C0731/journal.json`