These are the rotational puzzles present at the Shelob's Memory locations. The goal is to turn the fragments so they suggest an image. One strategy is to rotate it about until you see several similar elements close together (a bunch of shards that all have the same eye, for example). Focus on getting these to line up, and everything else should follow. The images for Minas Ithil are-
Under the Arena-
Under the Archway-
In the Cave Far to the South-
