# 📐 L2 Spec — Metamaterial / Metasurface — effective medium inversion Mismatch-Only Spec
**ID:** `L2-249-001` · **Status:** ⊙ Testnet (genesis catalog)
**Parents:** ⬆ Principle [`L1-249`](/artifact/l1/L1-249)
> **🎯 Tolerance (ε):** expression
> **⚖ Difficulty score:** 0.48 · **Delta tier:** 5
> **⛓ On-chain block:** 41554001
---
## 1. Domain Ω
**Type:** `range`
| Parameter | Unit | Range |
|---|---|---|
| Snr db | dB | 10 – 60 |
| N freqs | — | 11 – 10001 |
| Loss error | — | 0.0 – 0.2 |
| N unit cells | — | 1 – 100 |
| Spatial dispersion error | — | 0.0 – 0.3 |
| Unit cell geometry error | — | 0.0 – 0.05 |
## 2. Tolerance (ε)
**Type:** `fn`
```
18.0 + 0.25*SNR_dB - 50.0*unit_cell_geometry_error - 8.0*spatial_dispersion_error - 10.0*loss_error
```
## 3. Difficulty
| Property | Value |
|---|---|
| Difficulty score | 0.48 |
| Delta tier | 5 |
## 4. Fingerprint
`da4d59ca02e1bad6b22c73fde0c579911f439eade14675b244dae3ceadd83c59`
## 5. On-chain Registration
- **Chain hash:** `0x2d142276dcd723582f6fb610cded0380dc9c04ddfbc90e4908310bb5a9b19745`
- **Chain tx hash:** `0x2613e60bb236e632055c40388e29c0f727ad0c6afb1d8a2e7116d8d945915406`
- **Chain block:** `41554001`
---
## File Mapping
This bundle consists of: `L2-249-001.md`, `L2-249-001.json`.
| File | Role | How to regenerate |
|------|------|-------------------|
| `L2-249-001.md` | Source of truth — edit this | Human or LLM |
| `L2-249-001.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 `L2-249-001`._
_Edit it, regenerate the JSON, and submit at [/submit](/submit) to claim the artifact._