# C280 — LXX ON / restored MT realization of the triangle

24 September2026. Selected after C279 joined the8395 and17K families.

**All six598/8395/8993 triangles survive in the documented second realization.** Native cumulative LXX ON is paired with regular MT Cainan ON, Terah+60, full430. No SP companion is assumed in this Flood-only result.

|j|Cumulative Shem signed|Cumulative Flood partner signed|Reflected MT Flood|
|---:|---:|---:|---:|
|2|−6348|−5750|2645 G1 close|
|3|−6347|−5749|2646 G1 start|
|4|−6346|−5748|2647 G2 close|
|5|−6345|−5747|2648 G2 start|
|6|−6344|−5746|2649 G3 close|
|7|−6343|−5745|2650 G3 start|

Every row has598 between the two cumulative sources,8395 from cumulative Flood to reflected regular Flood, and8993 from cumulative Shem to that same regular Flood. The registered MT baseline values plus130 regular Cainan and60 Terah reproduce the bilateral source table exactly. Both seasonal components agree along both routes.

The equality of the coordinate displacement has two different explanations. Cumulative OFF→ON adds460 to the BC numeral and therefore subtracts460 from the signed center. On the reflected regular side, replacing SP by MT changes the BC numeral by−650, then the selected130 and60 restorations give−460. Thus the whole signed triangle is translated by−460. This is a comparison between qualified states, not one historical operation applied indiscriminately to every node.

No regular cumulative-Cainan460 operator has been introduced: regular Cainan remains130. No cumulative Terah+60 has been imposed. The native cumulative bases are5750 and6350; annual field indices retain their prior meaning and receive no Gear.

The result shows covariance of the complete triangle, beyond preservation of its8395 edge alone. It does not independently establish an absolute local placement. A corresponding change of local-map intercepts would be required to keep every local image unchanged; that requirement is a separate operation and was not imposed here.

Thirty-seven mathematical/domain checks and nine source-authentication checks pass. Two readouts replay identically. Author review only; canonical files and C127 remain unchanged.

**Best next bounded step — C281:** test the Noah side of this second realization. MT has no SP companion rail, so determine exactly which600 rectangles and598/602 crosspairs retain admissible Noah records. High is sufficient.