Loading collection data...
Collections are a way for you to organize kata so that you can create your own training routines. Every collection you create is public and automatically sharable with other warriors. After you have added a few kata to a collection you and others can train on the kata contained within the collection.
Get started now by creating a new collection.
Not a kata issue, your solution is wrong. It seems you're not retuning anything from recursion (because you had to post your code in a comment with a spoiler tag instead of making useless screenshots).