[hyperman1]

Back in the day, I saw someone ripping a CD to MP3s. He lazily named the first one 1.mp3, the seconde one 2.mp3 etc. After 9, he found he ran out of numbers. So the next one became ... A1.mp3 !

I always wondered, if he thought this trough a little bit further, he'd independently reinvent the arabic number systems.

[brimble]

Some interfaces will sort 10.mp3 so it's directly under 1.mp3, instead of under 9.mp3. This could be a totally sensible hack to evade that problem.

[aix1]

It even has a name: natural sort order.

https://en.wikipedia.org/wiki/Natural_sort_order