Project Euler hosts math challenges that can only be solved by writing programs. They are interesting by themselves, but I never took the time to start solving them.
However, a geocacher created some caches that can only be found by solving problems derived from this project.
To make things more interesting, I'll try to solve them using several programming languages, it will be a good excuse to start learning rust!
However, geocaching puzzle are often different than the one from euler, that's why I often give 2 different solutions.