a) Identify all rotation axes (2,3,4,6) and mirror planes (m) for the diamond unit cell. For each different type of mirror plane or rotation axis, draw an example of the symmetry element and indicate how many of that type of symmetry are present. If the same symmetry element exists along different equivalent directions of the unit cell, then you only need to provide one example of that symmetry element.
b) Show an example of an inversion rotation ('improper rotation') axis in the diamond unit cell. Sketch a view along the appropriate direction.