Chapter 422: Above Transfiguration
Regulus never asked about the window directly. Not one word of it.
But the theory he needed could come from McGonagall all the same.
She wouldn't hand him an answer about the Decomposition Curse. Transfiguration theory, though, could tell him whether applying a shape to something stripped of its true form held together logically.
If it did, the rest was execution.
How long the window ran, how to complete a transfiguration inside it, how to keep those basic units from scattering, all that was his own problem.
She was quiet a while, taking the idea seriously. It had depth, whatever else could be said about it.
Strip a thing until it was no longer defined as anything determinate, then confer a form on it there. That wasn't ordinary Transfiguration anymore. It touched the border between existence and form.
She'd turned over questions like it herself across a long career of study.
But she had decades behind her, and the child in front of her was a second year who had followed the inclination to return all the way to that border on his own.