> For the complete documentation index, see [llms.txt](https://docs.urbit.org/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.urbit.org/hoon/examples.md).

# Examples

Programming exercise solutions in Hoon covering algorithms like spell checking with blocks, competitive programming challenges, prime number calculations, path finding, and encryption implementations.

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.


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