To recognize a shape that has been rotated in an answer choice, what feature stays the same no matter how it is turned?

When a shape is rotated, its size, proportions, and the relative arrangement of its features (edges, corners, notches, and connection points relative to one another) stay exactly the same — only its orientation on the page changes. So to recognize a rotated shape, look past its angle and check that its dimensions and internal arrangement still match the original. For instance, an L-shaped piece turned 90 degrees is still the same L with the same arm lengths. Focusing on these rotation-invariant features lets you correctly match a turned shape and avoid rejecting a correct answer just because it looks different.