Re: Remnant decryption?!

"No highlighted shape can include repeats"

Those highlighted shapes are the shapes outlined by those thick blue lines (the 2 by 2 square in your case). Sometimes you get weird shapes consisting of 5 spots.

It's sudoku 🥳

So for example, the square in the upper left corner should be filled with the symbol consisting of two lines. The rest is for you to solve.