The paper says that more detailed discussion of partition methods is given in [15]. That looks like Sedwicks's Ph. D thesis which was on Quicksort?

I found this: https://sedgewick.io/wp-content/themes/sedgewick/papers/1975...

Basically a longer book on Quicksort with a lot more analysis.

He doesn't discuss any partitioning methods that do not move two indices toward each other from opposite ends of the subarray. It's not even on the table.

Of course the logo on the paper title page is a sequence of 8 lines with each doubling on thickness.

Though it'd be more visually and intuitively accurate if the lines started large and cut in half each step. :P

Nice catch, yes!