This process bears a certain resemblance to the forging of a masterwork katana and takes approximately as long. You have to be really careful to roll gently towards the end, because otherwise the squashed lumps will break through the thin layers of pastry. But you get a delicious multi-layered flaky pastry at the end. It's worth the effort, but it's not something you make a regular habit of. It's ideal for, say, Cornish pasties, which was what I was aiming for tonight.
Because it's not something you do regularly, I wasn't sure about the recipe so I decided to look it up in the closest thing we have to a Basic Cooking Reference: the Settlement Cook Book, 1965 edition.
Here is how The Settlement Cook Book says to make flaky pastry: make a basic shortcrust, but instead of half butter, half shortening, use all shortening but put in a quarter-cup more. This should, in retrospect, have made me suspicious.
Instead "Woohoo," went I, "lo these many years my labour has been wasted, when the antediluvian American housewife, in her constant struggle to hang on to her man's affections, knew the secret to quick and easy flaky pastry all along."
The antediluvian American housewife did not use the adjective 'flaky' to mean what I think it means.
I think I've salvaged the result. But Cornish pasties it ain't. Rrrgh.