What fault or fold is most difficult to diagram?

The most difficult fault to diagram is often the "thrust fault," particularly when it occurs at high angles or in complex geological settings. Thrust faults involve the horizontal compression of rock layers, which can create intricate folds and overlapping strata, making visual representation challenging. Additionally, the movement along these faults can lead to significant variations in rock displacement and layering, complicating accurate depictions. The interplay between thrust faults and associated folds can further obscure the geological relationships, adding to the difficulty of creating clear diagrams.