# Combined LEVEL3 Feature Document {#combined}

This document exercises all LEVEL3 constructs in a single file.

## Introduction {#intro}

This document demonstrates the full LEVEL3 feature set as described by [@smith2020].
See [Background][bg] for context.

## Background {#bg}

Context and prerequisites are discussed here. Refer to [Introduction][intro]
for the problem statement.

## Architecture {#arch-section}

The system architecture is shown below.

![System Architecture](arch.png){#fig:arch}

The architecture overview in [Architecture][arch-section] establishes the
baseline from which the data flow is derived.

## Data Flow

The data flow diagram illustrates message routing.

```mermaid
graph LR
    A[Input] --> B[Processor]
    B --> C[Output]
```

## Algorithm {#algo}

The algorithm formalises the approach described in [@jones2021].

```graphviz
digraph algorithm {
    start -> step1 -> step2 -> end;
}
```

## Results {#results}

Experimental results confirm the algorithm in [Algorithm][algo].

![Experimental Results](results.png){#fig:results}

The results align with predictions from [@brown2019] and the architectural
choices described in [Architecture][arch-section].

## Conclusion {#conclusion}

All LEVEL3 constructs — cross-references, figures, diagrams, and citations —
have been demonstrated. See [Introduction][intro] through [Results][results]
for the complete narrative.

## References

- [@smith2020]: Smith, J. *LEVEL3 Design Principles*. 2020.
- [@jones2021]: Jones, B. *Algorithm Formalisation*. 2021.
- [@brown2019]: Brown, C. *Experimental Validation*. 2019.