millerind() is a graphical user interface that gives a simple method to view and understand the underlying princples behind the Miller indices of a cubic crystal.

By entering a desired plane and pressing "Plot", the desired plane along with its orthogonal vector are displayed on the crystal cube, and all possible plane equivalents are shown. You can choose any of these planes to have them being shown on the axes, or you can rotate the cube manually and find out which equivalent plane results.