# Examples

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

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