A large block of Aluminum has a perfect cylindrical hole of diameter 3 meters. On top of the hole sits a perfect, solid glass sphere of diameter 3.05 meters. Your job is to get the glass sphere to traverse the hole in the block.
Oh yeah, when you are done, the block and sphere are indistinguishable (macroscopically and microscopically) from their condition before you started.
Is this possible?
It's a nice elegant problem, and theoretically works out. But if you expose the surface of a glass object to a thermal gradient of over 800 degrees, you're guaranteed to crack it by differential heating. Oh, and unless it's being carried out in an inert atmosphere, the aluminum won't likely be indistinguishable when you're done- the surface will undergo some oxidation, and probably some distortion too.
in principle....
