An interesting "application" are zip quines, where a compressed archive decompresses to itself. https://research.swtch.com/zip https://research.swtch.com/zip I

An interesting "application" are zip quines, where a compressed archive decompresses to itself. https://research.swtch.com/zip https://research.swtch.com/zip I recently built a zip quine that was simultaneously a valid PDF to show off, and the most fun part was making the CRC32 check succeed. If the checksum had been based on a cryptographic hash function, it would've been essentially impossible, but fortunately CRC32 can be reversed simply by solving a system of linear equations.