# 📐 L2 Spec — OCT Angiography (OCTA) Mismatch-Only Spec
**ID:** `L2-050-001` · **Status:** ⊙ Testnet (genesis catalog)
**Parents:** ⬆ Principle [`L1-050`](/artifact/l1/L1-050)
> **🎯 Tolerance (ε):** expression
> **⚖ Difficulty score:** 0.5 · **Delta tier:** 5
> **⛓ On-chain block:** 41553361
---
## 1. Domain Ω
**Type:** `range`
| Parameter | Unit | Range |
|---|---|---|
| H | px | 128 |
| W | px | 128 |
| Z | — | 256 – 2048 |
| Snr db | dB | 10.0 – 40.0 |
| N repeat | — | 2 – 16 |
| Eye motion | — | 0.0 – 0.5 |
| Decorrelation tail | — | 0.0 – 0.3 |
| Projection artifact | — | 0.0 – 0.3 |
| Signal strength variation | — | 0.0 – 0.3 |
## 2. Tolerance (ε)
**Type:** `fn`
```
17.0 + 0.3 * SNR_dB + 2.0 * log2(N_repeat / 2) - 10.0 * eye_motion - 6.0 * projection_artifact
```
## 3. Difficulty
| Property | Value |
|---|---|
| Difficulty score | 0.5 |
| Delta tier | 5 |
## 4. Fingerprint
`9a1550373d460db8b356c1e40736b70e1b6f6c68672f4d70e778164345a765ee`
## 5. On-chain Registration
- **Chain hash:** `0x12b0557d85c6eb4a68077457afd8ee88637f28ce9d86bf4667a11a61a7c355e8`
- **Chain tx hash:** `0xa55004cb81d315254e78d2fa120641d7a95326f425b3c2cdd8351b3987ad36e9`
- **Chain block:** `41553361`
---
## File Mapping
This bundle consists of: `L2-050-001.md`, `L2-050-001.json`.
| File | Role | How to regenerate |
|------|------|-------------------|
| `L2-050-001.md` | Source of truth — edit this | Human or LLM |
| `L2-050-001.json` | Structured metadata for the registry | LLM regenerates from the sections above |
**Prompt for your LLM after editing this Markdown:**
> Read the attached Markdown. Regenerate the sibling `.json` so every field matches.
> Preserve the schema documented in the rows above.
> Output each file in its own fenced code block tagged with the filename.
> Output only the JSON object.
_This Markdown was auto-synthesized from the catalog row for `L2-050-001`._
_Edit it, regenerate the JSON, and submit at [/submit](/submit) to claim the artifact._