# 📐 L2 Spec — Single-Pixel Imaging Mismatch-Only Spec
**ID:** `L2-026-001` · **Status:** ⊙ Testnet (genesis catalog)
**Parents:** ⬆ Principle [`L1-026`](/artifact/l1/L1-026)
> **🎯 Tolerance (ε):** expression
> **⚖ Difficulty score:** 0.42 · **Delta tier:** 5
> **⛓ On-chain block:** 41547812
---
## 1. Domain Ω
**Type:** `range`
| Parameter | Unit | Range |
|---|---|---|
| N pixels | — | 1024 – 65536 |
| Gain alpha | — | 0.0 – 0.003 |
| Dark offset | — | 0.0 – 0.02 |
| Illum sigma | — | 0.0 – 15.0 |
| Noise level | — | 0.001 – 0.05 |
| Sampling ratio | — | 0.05 – 0.5 |
## 2. Tolerance (ε)
**Type:** `fn`
```
22.0 + 6.0 * log2(sampling_ratio / 0.05) + 1.5 * log10(photon_count / 100)
```
## 3. Difficulty
| Property | Value |
|---|---|
| Difficulty score | 0.42 |
| Delta tier | 5 |
## 4. Fingerprint
`00d86d72500fdc70edb27268b2a6c3dcb654409f6ecbf9c4b808e142eb625278`
## 5. On-chain Registration
- **Chain hash:** `0xe00bbd702bea77fa264c2e37dd46007d310e55ff9937cf0b6a462a04ac735bb6`
- **Chain tx hash:** `0x36525562fb0cca91d7301576b397eac52c859f5dc18c36b38e74b17a1734d617`
- **Chain block:** `41547812`
---
## File Mapping
This bundle consists of: `L2-026-001.md`, `L2-026-001.json`.
| File | Role | How to regenerate |
|------|------|-------------------|
| `L2-026-001.md` | Source of truth — edit this | Human or LLM |
| `L2-026-001.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 `L2-026-001`._
_Edit it, regenerate the JSON, and submit at [/submit](/submit) to claim the artifact._