Ironically the particulars of this implementation make it much less efficient than a dumb bubble sort. Many Quicksort implementations have the worst performance on already sorted data, and in this case it will be run a lot on data that is already mostly sorted. It won't matter here because the data size is always trivially tiny, but it is something to consider in the real world.
Again, the need was not to implement an efficient sort. It was to implement an animation that pretends to execute an efficient sort. Also, quicksort gives a more interesting result visually.
