Put the shuffled tiles of a blend in the latent space back in order, as fast as you can.
Checking the server…Four random directions of the 128-dimensional latent space of the analysis backbone, at the norm of its embeddings.
Every cell mixes the four corners with bilinear weights of its position, back on the sphere of the embeddings, and is decoded as one partition without its value frame.
The decoder is smooth in its embedding, so neighboring blends decode to similar fields; a puzzle is kept only when every two neighbors still differ visibly.
Every wrong drop adds five seconds to the time, so trying every cell is slower than reading the board.