To the Hydra Cage
Look for the caged brick below the blinking HYDRA sign in the Hydra Empire.
Go right around the corner, and clear some random stuff away from the marvel vent there.
Enter the vent,then use the console for a sliding brick puzzle. As ever, you can easily solve it by just running its scramble moves in reverse. In this case, the bricks you want to move to restore the image are- top-right, top-middle, center, middle-left, top-left, top-middle, center, bottom-middle, bottom-right.
This completes the puzzles, and opens the brick-vault on the other side of the room.