Create a marimo notebook that guides a civil engineer through the step-by-step calculation process of <INSERT: CALCULATION/TOPIC> as specified in <INSERT: CIVIL ENGINEERING CODE OF PRACTICE, e.g. Eurocode 7 part 1 EN 1997-1, Clause 6.5>.

The notebook must have the following structure:

## Inputs
For each input parameter:
- Create a **Python variable** with a default value.
- Define:
  - Lower and upper bounds
  - A brief **description** (copied from the code of practice)
  - The **LaTeX symbol** as used in the code of practice
  - The **unit of measurement** as used in the code of practice

## Calculation
- Use subsections to mirror the code’s logic.
- Clearly describe each step in Markdown.
- For each calculation:
  - Reference the specific clause number in the code
  - Display the formula in LaTeX
  - Show intermediate steps with Python variables
  - Display intermediate and final results using formatted Markdown
  - Include charts, diagrams, or plots where helpful (e.g., bearing pressure vs. width, failure envelope, etc.).

## Results
- Present final results in a clean summary.
- Use Markdown to list final values with LaTeX symbols, units, and variable names.

Follow the code of practice document as closely as possible.
Prefer clarity over compactness. 
Use graphics where it helps the civil engineer understand the mechanics.
