I think partial transfiguration gains power by being a literal carving device. Normal transfiguration can force an object to take a shape, but they always revert. Partial transfiguration can carve pieces off selectively and have it be permanent. Eg, "the sculpture was always in the block of marble, I just removed what was not the sculpture." Although you'd need to set up incredible safety protocols. Presumably you'd transform the waste into a non-evaporative liquid while keeping a bubble headed charm on until you finite'd everything.
Harry Potter is his own little subtractive universal CNC machine. He's infinite axis; he can work on any material; he can work on any size. A mail order service could be a multi-million dollar a year business, depending on how tight he could control his tolerances. This goes doubly so because it's in 1991 compared to modern day.
Edit: Actually, I suppose sufficiently powerful wizards could do this too. They would just transfigure the whole block of steel into an engine+oil, drain it all, then finite it back so just an engine remained. And I don't think there's a big enough market for Harry to work exclusively on sculptures in the sides of the mountains or anything. Drat, foiled.
This is a new thread to discuss Eliezer Yudkowsky’s Harry Potter and the Methods of Rationality and anything related to it. This thread is intended for discussing chapter 81, which should be published later today. The previous thread passed 400 comments as of the time of this writing, so it will pass 500 comments soon after the next chapter is posted, if not before. I suggest refraining from commenting here until chapter 81 is posted; comment in the 12th thread until you read chapter 81. After chapter 81 is posted, I suggest all discussion of previous guesses be kept here, with links to comments in the previous thread.
There is now a site dedicated to the story at hpmor.com, which is now the place to go to find the authors notes and all sorts of other goodies. AdeleneDawner has kept an archive of Author’s Notes. (This goes up to the notes for chapter 76, and is now not updating. The authors notes from chapter 77 onwards are on hpmor.com.) When posted, chapter 81 should appear here.
The first 5 discussion threads are on the main page under the harry_potter tag. Threads 6 and on (including this one) are in the discussion section using its separate tag system. Also: one, two, three, four, five, six, seven, eight,nine, ten, eleven, twelve.
As a reminder, it’s often useful to start your comment by indicating which chapter you are commenting on.
Spoiler Warning: this thread is full of spoilers. With few exceptions, spoilers for MOR and canon are fair game to post, without warning or rot13. More specifically: