For a crystal with a cubic structure, sketch its unit cells showing the following crystallographic directions:
(a) [011], (b) [212], (c) [111], (d) [124], (e) [230].
For each sketch, keep the direction vector within one unit cell, using the fact that the direction does not change when all vector coordinates are multiplied or divided by the same factor. Explain your answer and mark the origin you have chosen in each case.