Recursion and Merge Sort

I was trying to understand merge sort. And I failed. Miserably. The problem was I was trying to understand the algorithm by my usual method of line by line printing variables to the console. This was fine until about half way through when it all fell apart.

The merge sort function was seemingly getting values out of thin air and it made no sense… Until I understood recursion.

Here is a video where I try and explain it.

Thanks to my son Marshall for being the cameraman!

https://www.youtube.com/watch?v=Yh89FCXJG