# Examples

Example solutions to programming exercises written in Hoon. If you've already [learned Hoon](/build-on-urbit/hoon-school.md), you can try to solve these yourself before reading the solutions provided.

* [ABC Blocks](/hoon/examples/abc-blocks.md) - Spell words with blocks.
* [Competitive Programming](/hoon/examples/competitive.md) - Various exercises.
* [Emirp](/hoon/examples/emirp.md) - Compute primes whose reverses are also primes.
* [Gleichniszahlenreihe](/hoon/examples/gleichniszahlenreihe.md) - The look-and-say sequence.
* [Islands](/hoon/examples/islands.md) - Find the size of the biggest island in a 2D grid.
* [Luhn Number](/hoon/examples/luhn-number.md) - Compute Luhn numbers.
* [Minimum Path Sum](/hoon/examples/min-path.md) - Find the least expensive path through a 2D grid.
* [Phone Letters](/hoon/examples/phone-letters.md) - Return the strings that can be represented by numbers in a phonepad.
* [Restore IPs](/hoon/examples/restore-ip.md) - Restore IP addresses that have lost their dots.
* [Rhonda Numbers](/hoon/examples/rhonda.md) - Compute Rhonda Numbers.
* [Roman Numerals](/hoon/examples/roman.md) - Printing and parsing roman numerals.
* [Solitaire Cipher](/hoon/examples/solitaire.md) - Solitaire encryption cipher.
* [Water Between Towers](/hoon/examples/water-towers.md) - Fill convex areas of a tower with water.


---

# Agent Instructions: Querying This Documentation

If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question.

Perform an HTTP GET request on the current page URL with the `ask` query parameter:

```
GET https://docs.urbit.org/hoon/examples.md?ask=<question>
```

The question should be specific, self-contained, and written in natural language.
The response will contain a direct answer to the question and relevant excerpts and sources from the documentation.

Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.